The second-largest cave chamber in the world was discovered in 1898 by a 16-year-old and a friend known as "Pothead."

A museum dedicated to the alleged Roswell Incident.

A magnificent waterfall nestled in the heart of the El Yunque National Forest.

Legend tells how a Spanish soldier disappeared from this isolated sentry box without a trace.

This colorful gate stands as an entrance to the walled city of Old San Juan.

This bleach-white graveyard overlooking the ocean is accessed through a tunnel.

This small fort played a huge role defending Puerto Rico’s capital city.

The bat-covered home of one of the world's most popular brands of rum is located on a tropical Art Deco campus.

A crumbling cathedral condemned by an earthquake.

The youngest volcano in Central America.

This elaborately decorated, fairytale-like Romanian royal palace is one of the most striking castles in Europe.

The bust of Romania’s most notorious ruler, Vlad Dracula aka "Vlad the Impaler," keeps watch over the ruins of his medieval court.

Historic beer hall in Bucharest with magnificent stained glass and a lively folk band.

This communist behemoth is the heaviest building in the world and a legacy of a brutal regime.

The kitsch mansion of the former Romanian president Nicolae Ceaușescu features a golden bathroom.

Romania's triumphal arch looks out over Bucharest.

Popular tourist destination where witches in dark hats sell dried llama fetuses for good luck.

This likeness of the famous revolutionary is entirely made of recycled scraps of metal.

Mysterious Incan ruins on a tiny island in Lake Titicaca.

A Norwegian-born sculptor created these soaring guardian angels at the entrance to Hoover Dam.

These markers are used to document elevation changes around the famed dam.

This balancing rock is one of Utah's most unusual geological formations.

The ancient dwellings of the Puebloans, located in the cliffs of majestic mesas.

Spectacular 300-foot cliffs in a lush mountain canyon.