In Chicago, a pizza-enthusiast has opened a museum dedicated to the history of pizza.

What was once one of the country's largest confectionary plants is now an abandoned ruin, but is still pretty sweet.

Once an ornate movie theater remade by Catholic Charities.

A chance to follow in the footsteps of the word's most legendary animator.

Where Cusack's record store from the film "High Fidelity" was located.

This modest post office sits on the site of H.H. Holmes' famous murder castle.

The beloved home to all publications indie, erotic, and punky.

This alley in downtown Chicago held the bodies of over 600 people after the fateful Iroquois Theatre fire.

Pizza with a side of fine art.

Chicago's largest cemetery is full of beautiful Victorian monuments and more than a few ghost stories.

An enormous park-like oasis, full of famous Chicagoans' graves.

Four glass boxes hover over 1,000 feet in the air to give visitors an unparalleled view of Chicago.

The enormous 250-room Vanderbilt mansion conceals hidden doors and secret passageways.

A beautiful and abandoned New York subway station from 1904, complete with chandelier.

An abandoned, decaying sculpture garden built by an eccentric physician in the 1920s now looks more like a forgotten cemetery.

Once home to a Scottish baronet, this 18th-century historic house doubles as a legendary art space.

This alley off Edinburgh's Royal Mile contains remnants of the city's seedier history.

This allegedly haunted 16th-century tower house-turned-museum exhibits thousands of spectacular objects.

This series of Scottish caves has no clear purpose other than baffling historians.

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

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

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

An unoccupied lighthouse encased in layers of ice from the waters of Lake Erie.

Abraham Lincoln's vice president took his last breath here on July 4, 1891.