1

Beehives

Image: Meggyn Pomerleau

The first entry on the list goes to perhaps the most famous and finest example of animal architecture: the beehive. Built by incredibly industrious insects, beehives are among the most efficient structures in nature .

The regular hexagons provide the least-perimeter way to enclose infinitely many unit areas in the plane: the best way to separate the surface of their hives in equal parts all around, using the least possible total perimeter, thus reaching 100% efficiency in design.

2

Ant colony

Image: Morten Jakob Pedersen

If beehives aren’t the first thing that comes to mind when thinking about animal architecture, there’s a good chance you’re thinking of ant colonies.

Ants build the elaborate colony structure by hollowing out the area with their mandibles, grain by grain, without a blueprint, without a leader, and in total darkness . Unless the soil dries out dramatically, the chambers will keep their form.

3

Prairie dog town

Image: Moritz Kindler

These cute creatures excavate their homes by digging burrows into the ground, primarily in the Great Plains of North America. The region experiences extreme seasonal weather variations from season to season, requiring their homes to be built to withstand extreme temperatures, floods, and fires.

These underground "towns" have nursery rooms, pantries, living quarters, and temporary refuges —each smartly separated to serve a specific purpose.

4

Beaver dam

Image: Derek Otway

Another famous animal architect, the beaver, uses felled trees to build dams . These dams create still ponds where beavers can construct their winter homes, called lodges.

These creatures prepare for winter by covering their lodge with a fresh coat of mud, which hardens to create a barrier against the cold and predators.

5

Caddisfly larvae case

Image: Wolfgang Hasselmann

Caddisfly larvae construct protective cases using silk and whatever materials are available , such as sand, small stones, and plant debris.

These cases camouflage the larvae from predators and can be remarkably diverse in appearance, reflecting their creativity and resourcefulness.

6

Octopus den

Image: Serena Repice Lentini

It’s no secret that octopuses are incredibly intelligent animals, and their dens are proof of it. These clever mollusks use shells, stones, and even discarded human objects to reinforce their homes . Some species go a step further, decorating their dens with seaweed and other found materials.

7

Bagworm silk tent

Image: Maëva Vigier

Bagworms construct silk tents around themselves using bits of leaves, twigs, and other debris . These tents serve as mobile homes, providing protection as the insect feeds and grows.

Some species even camouflage their bags to blend into the environment, helping them avoid predators.

8

Osprey nest

Image: Jorge Coromina

Ospreys build massive nests in tall trees or on human-made structures near bodies of water. These nests are carefully constructed with sticks and lined with softer materials , creating a sturdy platform that can last for multiple breeding seasons.

9

Coral reef

Image: Hiroko Yoshii

Coral reefs are massive structures built by tiny coral polyps. These marine architects secrete calcium carbonate to form hard skeletons, gradually creating vast and complex habitats for a myriad of marine species. They are often referred to as the "rainforests of the sea" due to their biodiversity.

10

Spider web

Image: freestocks

Another famous architect from the animal kingdom, the spider, creates webs that serve as both homes and hunting tools . The silk used in these webs is incredibly strong, and different species produce a variety of designs, including sheets, orbs, and funnel shapes.

11

Swallow nest

Image: Tobias Arweiler

Swallows build cup-shaped nests that can house entire colonies , using mud pellets, usually attached to vertical surfaces like cliffs or man-made structures.

The construction is precise and stable, providing protection for their young against predators and environmental elements.

12

Burrowing owl burrow

Image: mana5280

As their name suggests, burrowing owls make their homes underground , often taking over burrows abandoned by prairie dogs or other mammals.

They use these subterranean homes to protect their young and hide from the heat of the day.

1

French Quarter – New Orleans, LA

Image: João Francisco

Also known as the Vieux Carré ("Old Square" in English), the French Quarter is the oldest neighborhood in New Orleans. Established in 1718 by the city’s founders, the neighborhood is now famous for its vibrant music scene—particularly jazz, which was born in its streets and clubs.

Architecturally, the French Quarter is characterized by a blend of Spanish and French colonial influences, with wrought-iron balconies and colorful buildings lining the streets. Jackson Square and St. Louis Cathedral remain central landmarks, standing as reminders of the city’s rich European history.

2

Harlem – New York City, NY

Image: John Money

Harlem is a neighborhood in Upper Manhattan known for its African American culture and rich immigration history. Originally founded as a Dutch settlement around 1658, it was named after the city of Haarlem in the Netherlands. Harlem's complex history has been defined by a series of economic boom-and-bust cycles, with significant population shifts accompanying each cycle.

Successive waves of immigration populated its streets with people from all over the world, including Jewish and Italian Americans in the 19th century and African American residents in the 20th century. The Harlem Renaissance of the 1920s and 1930s cemented the neighborhood's fame, giving rise to figures like Louis Armstrong and Duke Ellington, and helping to shape American popular culture.

3

Beverly Hills – Los Angeles, CA

Image: David Vives

Although technically a suburb of Los Angeles, with distinct neighborhoods of its own, Beverly Hills is still a somewhat closed-knit community, known for its opulent homes and celebrity residents. Originally settled in 1828, the area began as an agricultural community centered around Rancho Rodeo de las Aguas, a Mexican-era land grant.

In 1914, a group of investors, initially searching for oil, discovered water instead and decided to develop the area into a town. By the 1920s, Beverly Hills had become synonymous with wealth and luxury, attracting movie stars like Douglas Fairbanks and Mary Pickford, who built lavish estates and cemented the area as a celebrity haven.

4

North End – Boston, MA

Image: Zoshua Colah

Boston's North End is the city’s oldest residential neighborhood, dating back to the 1630s. It played a crucial role in the American Revolution, with notable figures like Paul Revere building their homes there. The Old North Church, where the famous "One if by land, two if by sea" signal was sent, also stands as a landmark of the city’s revolutionary heritage.

The narrow streets and historic buildings offer visitors a glimpse into colonial America, making it one of Boston’s top tourist destinations. The North End is also renowned for its Italian heritage, which took root in the early 1900s, and for hosting the annual Feast of St. Anthony, a tradition dating back over a century.

5

Hollywood – Los Angeles, CA

Image: Jeremy Bishop

Hollywood is arguably the world’s most famous neighborhood when it comes to film and entertainment. Founded in the late 1800s, it quickly became the movie capital of the world with the establishment of the Nestor Film Company in 1911, the first of many studios to call Hollywood home.

Its most iconic landmark, the Hollywood Sign, was originally created in 1923 as an advertisement for a real estate development but has since evolved into a universal symbol of the film industry. While many production studios have relocated over the years, Hollywood remains synonymous with celebrity and filmmaking. Each year, millions of visitors flock to the Hollywood Walk of Fame and explore the streets where countless film legends started their careers.

6

Little Italy – New York City, NY

Image: Alex Haney

Little Italy, located in lower Manhattan, was established in the late 19th century by Italian immigrants who brought their culture, cuisine, and traditions to New York. The neighborhood quickly became a vibrant center of Italian-American life , with bustling markets, restaurants, and festivals.

Though urban development has reduced the original neighborhood to just five blocks, Little Italy still retains its old charm. Iconic spots like Lombardi’s, America’s first pizzeria, continue to draw crowds, while the annual Feast of San Gennaro—a tradition since 1926—celebrates the rich heritage of the community.

7

Chinatown – San Francisco, CA

Image: Kevin Vision

San Francisco’s Chinatown is not only the oldest but also one of the largest Chinese enclaves in North America —and even outside of Asia. Established in 1848, it holds significant historical and cultural importance, playing an important role during the California Gold Rush and the construction of the Transcontinental Railroad.

Today, Chinatown is celebrated for its vibrant markets, distinctive pagoda-style architecture, and lively Chinese New Year festivities. Spanning 24 blocks, it remains a crucial cultural and commercial hub, drawing both tourists and locals with its authentic cuisine and historic landmarks.

8

Hyde Park – Chicago, IL

Image: Manta X

Best known as the home of the University of Chicago, Hyde Park has long been a hub for intellectuals, politicians, and social movements on Chicago’s South Side. Originally developed as a retreat for the city's affluent residents, the neighborhood is also known for its numerous museums and religious institutions, including the famous Museum of Science and Industry.

Hyde Park was also the site of the 1893 World's Columbian Exposition, where millions of visitors were introduced to groundbreaking innovations, such as the first Ferris wheel. Today, it remains one of Chicago’s most diverse neighborhoods, having been home to notable figures like President Barack Obama.

9

Beacon Hill – Boston, MA

Image: Leslie Cross

Beacon Hill is one of Boston’s most picturesque neighborhoods, known for its Federal-style row houses and gaslit streets. Established in the early 1800s, it quickly became a haven for the city's elite, featuring homes designed by notable architects of the era, including Charles Bulfinch.

Beacon Hill also played a significant role in the abolitionist movement, with prominent figures like Frederick Douglass residing in the area. Adding to its architectural charm, the Massachusetts State House, also designed by Bulfinch, crowns Beacon Hill with its stunning golden dome.

10

Little Havana – Miami, FL

Image: Kian Lem

Little Havana in Miami is the heart of Cuban-American culture in the United States. Home to Cuban exiles and Latin American immigrants, the neighborhood's main street, Calle Ocho, is famous for its colorful murals, Cuban cafés, and lively music. Each year, the Calle Ocho Festival, part of the larger Carnaval Miami celebration, draws thousands of visitors.

A symbol of cultural integration, Little Havana features several significant landmarks, including the historic Tower Theater, which has served as a cultural bridge for newly arrived immigrants by offering films in both English and Spanish.

1

Seattle Underground City

Did you know the remnants of Seattle's original streets are still accessible? Beneath the bustling streets of modern-day Seattle lies the Underground City , a network of subterranean passageways that formed the ground level in the 1800s.

By the end of the 19th century, after the Great Seattle Fire, it was decided to rebuild the city at a higher elevation to combat frequent flooding . So, these original streets, sidewalks, and storefronts were buried, and with it, much of their history.

Guided tours take people through tunnels and ladders and retell real and eerie stories about the history of the Underground City.

2

Luray Caverns

Image: Robert Thiemann

Have you ever heard of the underground Stalacpipe Organ ? Not only is it a one-of-a-kind interaction between keyboards and cavern stalactites, but it is also the largest musical instrument in the world, according to Guinness World Records.

This instrument lives in the Luray Caverns, Virginia. It consists of an electric console that taps on these ancient stalactites of varying sizes to produce musical tones. A subterranean wonder, these caverns are also known for their extraordinary size , housing towering stalactites and stalagmites, mirrored pools, and delicate drapery-like calcite formations.

3

The Underground Gardens of Baldassare Forestiere

Image: Adrian Botica

This stunning subterranean retreat was built entirely by hand. Tucked under the sun-scorched landscape of Fresno, California, lie the Underground Gardens of Baldassare Forestiere . They are the life’s work of Baldassare Forestiere, a Sicilian immigrant who started digging in the early 1900s to escape the Central Valley's oppressive heat.

Over 40 years, drawing inspiration from ancient Roman catacombs , Forestiere carved an elaborate network of underground rooms, passageways, grottoes, and courtyards that span 10 acres.

A unique masterpiece, the gardens are open with guided tours that lead guests through beautifully designed spaces featuring skylights, arches, and alcoves. This oasis also boasts an array of fruit trees, including citrus, figs, and olives.

4

Ruby Falls

Image: Goodfreephotos_com

Colorful and breathtaking, the Ruby Falls is a geological wonder located inside Lookout Mountain near Chattanooga, Tennessee.

Hidden over 1,000 feet below the mountain's surface, this waterfall cascades 145 feet into a pool , making it one of the tallest underground waterfalls open to the public.

Visitors enter the mountain and descend via elevator. Then, they walk through stunning cave formations such as stalactites, stalagmites, and flowstone. At the waterfall chamber, multicolored lights –powered by renewable energy– illuminate the falls. Lantern-lit tours are also offered as a chance to visit the marvel with a different charm.

5

The Catacombs of Green-Wood Cemetery

Image: Joy Ernst

Arched tunnels of tranquil, sacred vaults lie beneath the Green-Wood Cemetery in Brooklyn, New York. Built in the mid-19th century, these catacombs were designed as a prestigious resting place for the city’s elite , prominent families.

While the catacombs are typically closed to the public, special events are sometimes organized to welcome visitors, such as art expositions, guided history tours, and candlelit tours seasoned with live music and storytelling.

Outside, where the sun does reach, await the serene landscapes and remarkable monuments of the cemetery, which is itself a National Historic Landmark .

6

The Lost Sea

Image: Roberto Nickson

The largest underground lake in America is in Tennessee. Hidden within the Craighead Caverns in Sweetwater, this enormous body of water lies in a cave system filled with fascinating formations, such as stalactites, stalagmites, and rare anthodites, also known as "cave flowers."

A National Natural Landmark, this lake marvels scientists, who are yet unaware of the exact extension of its waters. Those who visit can embark on a boat ride called "The Lost Sea Adventure," first walking inside the cavern before reaching a boat to navigate these ethereal sights.

7

Mammoth Cave National Park

Image: Sherin Jacob

The Mammoth Cave National Park is home to the longest cave system in the world . Located in central Kentucky, it extends over 420 miles of explored passages and many more likely undiscovered. Enormous chambers, underground rivers, a labyrinth of tunnels, and gypsum crystal formations can all be found at this site.

The park has been declared a UNESCO World Heritage Site and an International Biosphere Reserve. It also includes over 52,000 acres of protected land on the surface, renowned for its lush forests and diverse wildlife.

8

Carlsbad Caverns National Park

Image: Cason Asher

A large bat colony lives in the Carlsbad Caverns National Park in New Mexico, but that’s not its only charm. The park boasts over 100 caves, with its centerpiece being the immense Carlsbad Cavern.

The cavern includes the Big Room, one of the largest underground chambers in North America, spanning 8.2 acres. Visitors can descend via an emblematic natural entrance or by elevator, dropping 750 feet underground. Stalactite formations like the Giant Dome, the Hall of the White Giant, and the Chandelier are some of the caves' breathtaking highlights.

9

Indian Echo Caverns

Image: Magda Ehlers

The Indian Echo Caverns, which have been open to the public since the early 1920s, are carved into the limestone of the Appalachian Mountains. Located near Hummelstown, Pennsylvania, this site gets its name from the echoes heard within the cavern’s chambers , which were once believed to be mystical by Native American people in the area.

Unique, immersive sections of the caverns have names like the "Crystal Palace," the "Echo Room," and the "Wedding Room," where, yes, real weddings are sometimes held!

10

Wind Cave National Park

Image: Francesco Ungaro

Wind Cave National Park, located in the Black Hills of South Dakota, is one of the world’s largest caves, but that’s not what it’s most famous for. One signature sight here is the boxwork formation , a rare lattice-like pattern formed by calcite deposits.

The cave system stretches for over 140 miles, though much of it remains unexplored. Popular tours take guests through captivating features like the "Ribbon Room" and the "Crystal Palace."

Why is Wind Cave called that? Mainly due to the "wind" phenomenon that occurs at its entrance. The cave's air pressure causes the entrance to draw in or expel air, depending on atmospheric conditions.