A 90-foot-tall psychedelic "tree" on the side of the highway has baffled passersby for decades.

An earthwork sculpture built by Robert Smithson in the Great Salt Lake only reemerges during drought.

The largest island on the great salt lake is home to curious creatures and strange stories.

This concert pavilion on the shore of the Great Salt Lake has been destroyed by fire, water, and disinterest but keeps coming back.

The ancient latrines of the Greeks, in all their public glory.

This crumbling medieval basilica once attracted pilgrims by the thousands to collect a miraculous dust that formed above the saint's tomb.

Carvings in Turkey's Marble Road may have directed ancient Romans to a hidden brothel.

A charming beach town in Turkey captures all the colors of the rainbow.

Ancient serpentine sacrifice holder that has stood the test of time.

This remarkably well-preserved Egyptian plinth is pretty well traveled for a giant piece of stone.

A fountain standing as a testament to a doomed alliance.

Legend says if you stick your thumb in the hole and it gets wet your wish will be granted.

Turkish adventurer antiques in the heart of the Grand Bazaar.

This column celebrates Rome's victory over the Goths, and may be the oldest Roman monument in Istanbul.

Taking the subway here means doing so over a bridge located in the middle of an estuary.

While not Turkey's deepest underground city, this subterranean redoubt is the largest.

Mausoleum and Holy Seat of Antiochus I of Commagene.

The deepest underground city in Turkey was designed to protect 20,000 people behind massive stone doors.

A Turkish ghost town abandoned in a population exchange with Greece.

A marvel of Byzantine engineering under the streets of Istanbul.

Roman ruins top white travertine terraces formed by ancient hot springs.

In this historic region, homes and churches are carved into ancient volcanic rock formations.