More sculpture than building, this architecturally significant temple was built on the spot of Saint Peter's crucifixion.

This former Roman Catholic Church still contains the embalmed hearts and organs of 22 popes.

Jesus' footprints and the first catacombs in the world.

The engineering wonder and pleasure dome of a much-maligned emperor still holds undiscovered secrets.

As can be expected from a centuries old church built in a canal city, the undercroft of this house of worship is beautifully flooded.

2300-year-old Roman road connecting the empire.

The underground sanctuary of a mysterious ancient cult.

A master of trompe-l'oeil creates a stunning, tourist-fooling dome out of a flat ceiling.

The crypts of Capuchin friars decorated with the bones of over 4,000 friars, including an entire "crypt of pelvises."

Named in tribute to Canadian singer and songwriter Neil Young.

Beautiful scenery, history, science, and physics come together in this remnant of shipping lore.

This 1836 church, constructed by formerly enslaved people, honors a leader in Afrocentric music.

This 12-seat movie theater is the smallest in the world.

Over 60 chemical plants and oil refineries sit in a 15-mile-wide section outside town.

Only six people can sit inside this delightfully quaint sanctuary.

This seemingly cursed monument is dedicated to one of Canada's great war heroes.

This impressive working clock made of 16,000 plants changes its flowers twice a year.

The giant birds honor two native North American species.

An abandoned 1970s theme park that has been turned into a space for waterfront walking.

This Niagara Falls tourist trap is a world bright with neon and curiosities that will inspire love, hate, or a mixture of both.

A collection of more than 12,000 shoes, displayed in a building shaped like a shoebox.

Soaring over the Niagara Whirlpool since 1916.

One of the Seven Wonders of the Modern World holds the world's tallest metal staircase.

According to local lore, this narrow passageway through two large rocks was accidentally created by the devil himself.