Controversial tribute to the heavyweight champion boxer who grew up in Detroit.

The only surviving prototype for Buckminster Fuller's house of the future.

A sealed test tube said to hold Thomas Edison's dying breath was given to the inventor's friend and mentee, Henry Ford.

Whisper secrets in a busy station only to be heard on the other side of this acoustic arch.

There must be a pun in this haystack somewhere...

This mosaic dedicated to John Lennon was tended for years by a Beatles super-fan.

This cemetery has graves dating back to the 17th century, including the city's oldest carved tombstone and an ominous cryptogram.

This sculpture by artist Fritz Keonig survived the 9/11 attacks and now stands as a monument to the victims.

An Irish Memorial commemorating those who perished due to potato blight.

The first American department store, and home to the largest operating musical instrument in the world.

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

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

A layered tribute to the work of mosaicist Isaiah Zagar.

Live long and prosper in Tennessee.

A bizarre roadside attraction and the first instance of miniature golf in the world.

An art museum with an eclectic design and a scandalous past.

A snake farm famous for its venemous varieties.

The massive gardens and office of a Brazilian sculptor.

Solitary monument dedicated to the beauty of nature.