Architecture lovers won’t stop touching the National Gallery's 19.5 degree marble prow.

An unassuming, powerful monument north of the U.S. Capitol bears witness to the resilience of Japanese Americans during a time of grave injustice.

The first presidential bomb shelter was located in an old vault under the Treasury, connected to the White House via tunnel.

Senators used to relax in the nearly forgotten marble tubs now hidden in the U.S. Capitol Building's basement.

"The prettiest love letters in the world" ... or so said Lord Byron.

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

This ruined quarry once produced the distinctive red sandstone used for construction projects in Washington, D.C.

She stares out across six lanes of traffic, clutching a musket and infant with determination.

A bas relief commemorates the "Nuns of the Battlefield" who cared for soldiers on both sides of the conflict.

The beloved statue at the National Academy of Sciences is oh so inviting to sit on.

This mighty white oak in Bethesda survived both the American Revolution and the construction of Washington D.C.'s metro red line.

A giant glider—designed by the father of the Rubik's Cube's designer—now soars within a shopping mall.

This quaint Hungarian railway system is operated exclusively by children between the ages of 10 and 14.

The world’s first statue of the late Apple co-founder.

This statue honors one of Budapest's most beloved literary characters.

From Austrians to Nazis to Soviets, this historic Budapest fortress has a history as complex as the city itself.

This Slovakian statue of an emerging sewer worker might just be a bronze peeping tom.

This spaceship sculpture in the middle of the Slovakian capital looks like it just crash-landed.

Museum devoted to the artificial language of Esperanto.

A small museum filled with over 1,000 clocks, and one particular clock calibrated to run until the year 9999.

The remains of an ancient Roman city are hidden underneath Bologna's beautiful public library.

Over 100 towers were built in Bologna during the Middle Ages, but only 22 survive.

The oldest church in Mantua was buried for centuries under the facades of other structures.

This palatial spiral staircase was so unusual the name "snail" was given to the noble family who built it.