Remnants of the most densely packed city in world history, that thrived on anarchy for 30 years.

A solemn reminder of the infamous World War II war crime that massacred almost all the men in a small Greek town.

There's a 12-foot-tall replica of the Washington Monument hidden under a manhole nearby.

London's creepiest cemetery was once the site of dueling magicians and mobs of stake-carrying vampire hunters.

The original resting place of Queen Cleopatra and Mark Antony's only daughter.

The ruins of an ancient Roman tomb hidden in the basement of a trendy clothing store.

Site where Moses may have received the Ten Commandments.

Within the Saudi Arabian desert lies a 2,000-year-old ghost town made of stone and mud.

More than 100 monumental tombs carved into rock are preserved at this ancient Nabataean site in the Arabian Desert.

An unfinished tomb carved into a giant boulder in the Arabian Desert.

A painfully obvious spy house sits right across the street from the Russian Embassy.

This titanic Catholic church in Chicago is also a refuge of the fictional cult-favorite wizard detective Harry Dresden.

These quaint cottages feature built-in signaling devices for fishermen.

A rare surviving Victorian greenhouse designed specifically to house giant water lilies.

Few of the many visitors to this resort town know of its hidden Maya ruins.

The plunge pool is a surviving relic of a rowdy royal residence.

Come for the boats, stay to explore the intriguing assortment of art.

A striking glass tribute to two sisters who suffered during Scotland's "Killing Time."

These bleak 800-year-old ruins were once the royal residence of choice for hunting in Sherwood Forest.

Used as an example in one of the first dictionary entries for "museum" in 1706.

A hidden plaque is the only reminder of the lost palace where two storied English kings were born.

Part museum, part piece of Arthurian-inspired history, this stately hall attracts King Arthur fans from miles away.

These legendary stone steps were once used to haul coffins up the rockface.

One of the few places where you can visit a cenote and Maya ruins at the same time.