A curious structure built just for the birds.

The one-time stronghold of the noble Douglas family, now home to ghost sightings and nesting birds.

Ruined 11th century abbey built by King David I in Edinburgh, Scotland.

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

A grand New York post office that is home to mailman Santas, scraps of postal history, and a pneumatic mail system.

A three-story copper skybridge connects two Manhattan buildings with Art Deco luxury.

This historic address is home to the beloved ball and is an almost totally empty building among the most expensive real estate in the world.

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

This stately monument has been wearing a traffic cone hat for decades much to the delight of the locals.

One of the oldest scientific gardens in Britain, containing more than 13,302 plant species in its core collection.

A six-ton wedding present for the King of the Scots.

The most loyal of little dogs, or a Victorian era publicity stunt?

17th century streets hidden under Edinburgh were once a breeding ground for the black death.

Old-fashioned knowledge and modern engineering create the world's only rotating boatlift.