Thousands of coffin-like pillars make up this controversial Holocaust memorial.

Cold war icon and onetime "hole" in the iron curtain.

The most visited, and possibly most controversial, museum in Germany.

On the Spree bank, discover one of the last reminders of a symbolic wall that divided, and was torn down by the people.

For patriotic Russians, this memorial honoring the Soviet soldiers who died liberating Berlin in 1945 is the most sacred location outside of Russia.

Fantastic views and thousands of love locks.

Underwater art project will double as a massive artificial coral reef to help regenerate the damaged ecosystem.

A small collection of iguana-infested ruins hides amid Cancún's bustling hotel zone.

These azure waters were thought to lead to the Mayan Underworld.

No telescopes, no power, no gift shop: The Observatory of Chichen Itza, one of the world's oldest observatories, takes astronomy back to basics.

Every equinox this Maya pyramid puts on a spooky ancient light show.

Clap your hands at the base of the pyramid, and the song of a sacred Mayan bird will echo through the air.

66,000 pieces of art, donated by one of the world's richest men.

A bronze statue of the famed Prussian naturalist commemorates the year he spent in Mexico.

These haunting ruins of a 700-year-old Prehispanic city have witnessed centuries of wars and massacres.

Dating back to the second century, vestiges of prehispanic mural paintings are found in this underground palace.

This ancient monastery complex was transformed from an island to a peninsula when the lake was partially drained.

This Armenian monastery was carved out of cliffs and named after the spear used to stab Jesus.

A geological oddity topped with a 2,000-year-old pagan temple.

This little medieval church hidden in the center of Yerevan was lost and rediscovered—twice.

A monument commemorating the 852 lives lost in the sinking of the MS Estonia.

During the Soviet era, the spire of this longstanding church was used as a radio transmission tower.

Walk along the medieval fortifications that have been protecting Tallinn since the 14th century.

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