This valley of hot springs and boiling mud pots is home to the record-holding "Geysir," which originated the English word.

This eye-popping Icelandic crater lake is surrounded by red volcanic rock.

The unique waterfall in Iceland's south features a backdrop of geometric black lava columns.

A museum dedicated to the tragedy of Bloody Sunday.

Achill's most recently abandoned village dates back to to the Age of Enlightenment.

Oliver Cromwell once seized the land under this house, which included the ruins of a medieval abbey that the owner used to build his stately home.

This Bronze Age tomb is the centerpiece of a clearing within a beautiful Irish forest.

An underwater statue of Christ blesses the depths off Key Largo.

Welcome to old Florida, where a 1940s mermaid show is still enchanting visitors.

The only swimming pool listed on the National Register of Historic Places is emptied and refilled each day with naturally filtered water.

One of the most remote spots in America and the first protected wilderness area in Nevada, named after an old legend.

Nevada's largest cactus collection stands outside a candy mogul's small factory.

The longest living non-clonal organisms on Earth.

The tragedy of the Japanese internment camps is remembered here by a stark "Soul Consoling Tower."

The echoes of a railroad town that solemnly mark the end of the line.

This park on the outskirts of Rome boasts two ancient Roman aqueducts and a medieval tower.

Ancient ruins hidden underneath a modern luxury hotel.

This historic recreationist school churns out warriors that may very well have had a fighting chance in Rome's pits of the day.

The mystic whose incorrupt corpse still attracts the faithful.

Brass cobblestones mark the places where individual Holocaust victims were taken from their homes.

The spot where the fascist dictator made some of his most famous speeches including declaring war on Britain and France.

The "Greatest Sewer" of ancient Rome is one of the oldest sewer systems in the world, and is still in use.

This Roman arch marks the location of an ancient gate at one of the Seven Hills of Rome.

This ancient Roman prison is decorated with an upside-down cross not as blasphemy but as saintly tribute.