Berthed at the Charlestown Navy Yard in Boston, "Old Ironsides" is the oldest commissioned warship still afloat.

This 4,000-foot-diameter hole is touted as "the most well known, best preserved meteorite crater on Earth."

This abandoned NASA launch site is now a memorial to a trio of astronauts who were killed there.

This outdoor gallery of graffiti-covered walls pays homage to the past, present, and possible future of street art.

One of the most enjoyable bits of history at Coney Island and “the most romantic ride in the world.”

This 1,300 year old monastery built atop a single rock was once only accessible depending on the whims of the tide.

This historic, palatial theater is now one of the world’s most beautiful bookstores.

The design of the Palacio Salvo has been described as "a lighthouse on top of a building."

A huge boat-shaped hotel with a blood red pool and other oddities.

A series of waterfalls so massive they straddle the border of Argentina and Brazil.

This attraction is devoted to the wonders of steam power and features a replica of one of its most public disasters.

High atop the Eiffel Tower is a small apartment built exclusively to entertain the science elite and make the rest of Paris jealous.

A 16th century chapel decorated with bones, skulls, and entire bodies hanging from the wall.

A unique seaside cave where Aleister Crowley faked his own death.

This eccentrically decorated palace is replete with grottoes, fountains, tunnels, and caves.

An ancient and majestic fortress that played an integral role in Portugal's road to independence.

This unreal Portuguese palace looks as though it's made from a pile of different castles.

A king's pet, a pope's gift, an artist's inspiration, and a tragic shipwreck.

Elaborately carved to showcase the glorious wealth that the age of exploration brought to the Portuguese empire.

This Industrial Age architectural and engineering gem helps visitors and residents alike traverse Lisbon, “The City of Seven Hills.”

A pedestrian island in the middle of world-famous Times Square emits a strange (and purposeful) humming noise.

Elevated freight railway turned wildly successful urban park.

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

One of São Paulo's tight urban intersections has become a haven for graffiti artists ever since a single Batman started the trend.