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

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

The ancient mosaics here are considered among the finest in the world, and serve as a stunning record of Greco-Roman daily life.

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

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 dark patch of the ceiling at Grand Central Terminal which was not restored is still stained brown by tobacco.

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

Once the tallest building in the world and the site of "the highest dinner ever held in New York" this building now holds the most expensive penthouse in the city.

The only visible reminders of an elaborate engineering project that kept the tower from reaching the tipping point.

This bustling Italian plaza is built on the ruins of an ancient Roman amphitheater.

A dismembered holy head stares out from her beautiful reliquary at the St. Dominic Basilica.

These medieval skyscrapers dominate the skyline of this small Tuscan town.

This strange bovine gargoyle is said to have been put in as a passive aggressive form of revenge.

This medieval Estonian tower provides access to a series of tunnels that have been home to soldiers, punks, and fine art.

The oldest church in the Estonian capital is home to over 100 fantastical cemetery coats-of-arms.

The Guardian of Tallinn.

An abstract monument to a symphonic composer.

The design of this beautifully crafted building was inspired by Norwegian glaciers.

Stockholm's decidedly unique public transit system has doubled as the world's longest art gallery for decades.

Danish tourist destination well known for open stalls where vendors sell marijuana on the street.

Climb inside an iron crystal magnified 165 billion times its normal size.

A little sculpture with a large wardrobe.

One of Catholicism's four major basilicas has a series of papal portraits that are said to predict the end of the world.

Jesus' footprints and the first catacombs in the world.