A chain of 16 wondrous lakes formed as a result of the gradual dissolution of soluble layers of bedrock.

According to a local legend, this old castle could only be built after a woman was immured in the walls.

A mesmerizing reservoir nestled at the heart of a pre-Islamic Yemeni village.

A sinkhole and now a swimming hole, too, full of dazzling turquoise water.

Human ancestor’s 3.6 million year-old footprints.

The history of those incarcerated in Singapore during World War II is etched into the bricks of a popular staircase.

The highest pedestrian bridge in Singapore looks like a series of undulating waves rising between two public parks.

This rare wildlife haven in Singapore feels like you're in the tropical rainforest.

This Cambodian riverbed is covered in ancient Hindu carvings both above and below the waters.

Thousands of artifacts tell Mongolia's military history, from the Bronze Age to the present.

A jagged silhouette of shamanistic stone heaps rises from the shore of this dazzling mile-high lake.

Dinosaur eggs were first discovered at these fiery red cliffs.

An exceptional assortment of fossils recovered from private collections.

A huge communist-era propaganda monument and mural that offers stunning views of the Mongolian capital.

The oldest Buddhist monastery in Mongolia has survived centuries of invasions, political shifts, and religious purges.

Enormous statue of the Emperor of the Mongols.

The grassy landscape is home to the world's last truly wild horses.

Every winter, dozens of otherworldly ice structures sprout up from a rigged up artesian well.

With its vast selection of books, comics, and records, this nearly 70-year-old open-air market always rewards the patient browser.

One artist’s scheme to expand museum viewing hours into the evening led to the illumination of an entire city.

A former Latvian headquarters of the brutal KGB secret police is now open as a grim reminder of their atrocities.

Relics from an era long gone, sit idle outside this Estonian museum.

A forest park outside Tallinn full of architectural and artistic curiosities.

An empty relic of the Moscow Olympics crumbles away in Estonia's capital.