Dr Barnes' $25 billion private collection of art and arboretum.

In the early 1800s, surgery was also a show.

A rare view of a preserved Victorian science museum.

America's most famous museum of medical oddities is home to the remains of Albert Einstein's brain.

A layered tribute to the work of mosaicist Isaiah Zagar.

The history of the tea trade is told in bas-relief on this historic pair of Boston doors.

The former site of an all-but-forgotten colonial landmark is now remembered by an often overlooked bas relief.

A mysterious stone embedded at the base of a historic Boston building.

19th-century operating theatre in which the use of ether was first demonstrated - plus, a skeleton and a mummy!

Giant origami sculptures tucked into desert scenery beckon passers-by to explore further.

A bigger-than-life pun that has become a beacon of altruism.

A classic Route 66 landmark that was built with scrap lumber and is held together with kitsch and puns.

This haunted corpse of a drive-in is now a graffiti-covered ruin.

This huge, disused viaduct is now a crumbling concrete underworld of covered in years of graffiti.

A bronze monument to the infamous radio broadcast in the real New Jersey town where the fictional Martians crash-landed.

Spinning silently in the lobby of an Art Deco masterwork is a massive vintage model of the Earth.

This massive boulder is either a unique rock formation created by glacial melt or a magic energy vortex.

Hidden in Central Park's Ramble is a troublesome cave buried just beneath the surface.

Curious crustaceans support an obelisk from ancient Egypt that now stands in modern-day Central Park.

A hyper-luxurious, 12,000- square foot home might be buried beneath Queens, still waiting to protect you from nuclear missiles.

The remains of a community that was forced to move for a dam that never materialized still rot in this Pennsylvania park.

Buildings that dynamite couldn't bring down were abandoned because of bathroom issues.

Over 100 concrete munitions bunkers are all that remain of a Pennsylvanian village seized by the US government.

An abandoned stretch of highway, deteriorating next to the operational one.