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

A faded sign from the 1920s remembers Baltimore's resistance toward banning alcohol.

Celebrating the transformation of trash into objects of beauty.

'Cause the fence start shaking, the earth was quaking.

A museum, art project, and institution that demands we look at the world around us in a strange new way.

This historic spot was where America's involvement in the Vietnam War officially came to an end.

A whimsical brother of the nearby Fallen Angel statue takes the falling part quite literally.

The only urban monument in the world designed by the great surrealist painter Salvador Dalí.

Shrapnel scars and bullet holes from the Spanish Civil War can still be seen in this monument to Spanish doctor Federico Rubio.

These three pillboxes still remain as a witness of the Spanish Civil War in a park of Madrid.

Petrified footprints of one of the very first vertebrates to walk on land.

The first mechanized factory in Spain is also one of the most significant mints in the history of money.

On the wall of this medieval walkway, a symbol of the Spanish Inquisition.

The U.S. government built the million-pound stack of steel during the Space Race.

This golfball sized platinum iridium cylinder is the official starting point for all national weight calibrations

Its diverse collection of computers and technology spans the ages.

A lawn full of retired spacecraft on display at one of NASA's first research labs.

Brain collection and database that narrows the gap between man and animal.

Fascinating museum dedicated to the under-appreciated medical history of urology features some wince-inducing devices.

An intricately designed junk art house with four extravagant junk art cars hidden in the suburbs.

The world's only flying boat museum honors a small Irish village that sent 20th-century aviation to new heights.

A strange egg in a mucky bog of western Ireland marks the spot of an aviation milestone.

This supermarket offers shoppers a window into the past alongside their groceries.

Surrounded by a verdant garden and a backdrop of ivy, a monument to beloved poet Khalil Gibran stands outside of the Lebanese embassy.