Coral Castle: Florida’s Mysterious Stone Castle

In Homestead, Florida, a collection of massive stone walls, carved furniture and bizarre sculptures serve as testimony to the extraordinary ambition of one man. Known as Coral Castle, the site was created by Edward Leedskalnin, a Latvian immigrant who spent decades shaping and arranging heavy blocks of local limestone. He worked largely by himself, using tools and mechanical devices rather than modern construction machinery.

Coral Castle is a remarkable stone sculpture garden created by Edward Leedskalnin.

Ilha da Queimada Grande: Brazil’s Infamous Snake Island

About 35 kilometres off the southern coast of São Paulo, Brazil, a small, forested island rises from the Atlantic Ocean. From a distance, Ilha da Queimada Grande looks like an ordinary patch of green surrounded by blue water. Its steep, rocky shoreline and thick vegetation, however, conceal something unusual: a venomous snake found naturally nowhere else on Earth.

Ilha da Queimada Grande rises from the Atlantic Ocean off Brazil's southeastern coast.

Pando: The Trembling Giant of Utah’s Aspen Forest

In Utah’s Fishlake National Forest, a grove of quaking aspens hides a surprising secret. Thousands of white-barked trunks rise from the ground, spreading across the mountainside. In autumn, their leaves turn a rich golden yellow; when the wind picks up, the canopy seems to ripple.

Pando is an enormous, quaking aspen clone in Utah’s Fishlake National Forest, known for its interconnected root system.

Torre de Vallferosa: Catalonia’s Mysterious Double Tower

Hidden among the wooded hills of Catalonia, Spain, stands a tower that looks as though one stone building has grown around another. Torre de Vallferosa rises above the surrounding countryside with a rounded profile, thick walls and a crown of battlements. From a distance, it resembles a conventional medieval watchtower. Its construction, however, is far more unusual.

Torre de Vallferosa rises above the countryside near Torà in Catalonia.

Great Serpent Mound: Ohio’s Ancient Serpent-Shaped Earthwork

In the rolling countryside of southwestern Ohio, a giant serpent winds across a grassy ridge. Its body bends into sweeping curves, its tail curls into a spiral, and an oval shape marks the area near its head. Seen from the ground, the full design is difficult to take in. From above, the outline becomes clear: this is the Great Serpent Mound, one of North America’s best-known prehistoric effigy earthworks.

The Great Serpent Mound forms a winding serpent-shaped earthwork on a ridge in southwestern Ohio.

Norias of Hama: Syria’s Giant Historic Waterwheels

Huge wooden wheels tell a story of engineering that predates electric pumps and modern water systems in Hama, Syria, along the Orontes River. Their broad rims, wooden compartments, and elevated aqueducts were designed to solve a simple but important problem: how to lift river water high enough to reach the city’s gardens, houses, mosques, and public baths.

The Norias of Hama are traditional wooden waterwheels built along the Orontes River to lift water into elevated channels.

Figure 8 Pools: Australia’s Unusual Natural Rock Pools

On the southern coast of Sydney, the Pacific Ocean has created something that looks almost too neat to be natural. Cut into a wide sandstone platform in the Royal National Park, the Figure 8 Pools are a collection of shallow rock pools, including one famous formation shaped remarkably like the number 8.

The famous Figure 8 Pool is a natural sandstone formation shaped by the long-term action of ocean waves.

Yangshan Quarry Stele: China’s Giant Unfinished Monument

Hidden in the hills of Nanjing, China, are three enormous pieces of limestone that were meant to become one of the largest stone monuments ever attempted. They are known collectively as the Yangshan Quarry Stele, a colossal project ordered in 1405 by the Yongle Emperor of the Ming dynasty. The plan was to create a monumental stele in honour of his father, the Hongwu Emperor, at the Ming Xiaoling Mausoleum.

The enormous unfinished base of the Yangshan Quarry Stele.

Derinkuyu Underground City: Ancient City Beneath Cappadocia

Deep beneath the town of Derinkuyu in central Türkiye lies one of the most remarkable underground settlements ever carved into rock. The Derinkuyu Underground City is not simply a collection of caves. It is a carefully planned subterranean complex containing rooms, storage areas, stables, places of worship, a school, wells, ventilation shafts, and narrow passageways. 

A view inside the multi-level underground city of Derinkuyu in Cappadocia, Turkey.

Waitomo Glowworm Caves, New Zealand

Deep beneath the green hills of Waikato lies a place that seems almost unreal. The Waitomo Glowworm Caves are famous for a dark underground chamber where thousands of tiny blue-green lights shine above visitors like stars in a night sky. The experience is especially memorable because visitors view the glowworms from a quiet boat moving along an underground stream.

A spectacular glowworm cave in New Zealand creates a starry-sky effect, with hundreds of tiny lights glowing against the darkness.