Places meltingknight Wants to Go

The heaviest gold coin ever minted.

This railroad track was so secretive that it was omitted from all maps.

Approximately 300 million years ago, a massive coral reef existed in what is now the largest limestone cave in Japan.

One of Mexico's least-visited archaeological sites is tucked away inside a theme park.

This ancient castle has been abandoned since the Edwardian conquest of Wales.

The last remnants of a massive medieval wall that once encompassed the city of Berlin.

The hilltop town of Segni was once home to an ancient Roman colony and garrison.

These ruins once flourished as the capital of the Lydian kingdom, often credited with the invention of metal coinage.

Deep in the Negev Desert, the world's tallest solar tower looks like a sight straight out of science fiction.

Knights Templar are visible inside this stunning Cistercian abbey.

This medieval city gate is now a blend of the past and the modern world.

Named after a lodging site that existed nearby, a bridge has existed at this location since 1455.

This runestone once destroyed by an explosion has been painstakingly reassembled to save its history.

An ancient Phoenician citadel once stood at the site where Queen Dido first landed, according to legend.

A Viking man's tribute to his brother stands in Gävle's oldest church.

A tangible and sobering reminder of an atrocity that took place during a secret war.

At one of Berlin’s oldest churches, visitors can place mosaic tiles to help restore a medieval mural.

This museum is dedicated to the cultural history of tobacco and salt, once monopolized in Japan.

The United Arab Emirates's biggest and oldest fort pays homage to a lost era.

Across Ring Mountain is a vast collection of Native American petroglyphs unique to the region.

A historic shipbuilding town is home to a sail-through fish-and-chips shop.

A magnificent waterfall is also home to the remains of a Roman hydraulic engineering system.

This 19th-century monument served an important purpose for fishermen thanks to its built-in barometer.

This mysterious ancient arch is hidden in the forest of Simbruini Mountains Regional Park.