This once-forgotten oasis in the middle of Lisbon was first created over a century ago quite by accident.

Portugal's National Pantheon has a history of curses, collapses and financial problems.

Located in the thermoelectric factory that once powered the entire city, this Portuguese museum is shockingly fascinating.

Hidden beneath a beautiful overlook you’ll find the history of the city depicted in comic strip format next to a pay toilet.

The best place in the world to buy tinned fish.

A small stone monument marks the spot on Stavely Road where the first of hundreds of missiles touched down during World War II.

Feast on buckets of garlicky snails.

Get in line for Lisbon’s most famous sandwich.

The remains of a military communications outpost still stand on this Greek island.

The abandoned summer estate of the former Greek Royal Family.

An intricate network of underground tombs carved into volcanic rock.

A glorious pub known for a spiteful printing feud and its famous typeface lost—then found—at the bottom of the Thames.

These docile dragons are ideal inhabitants for the conservatory greenhouses.

The fences outside some of South London's estates are made from recycled World War II stretchers.

Mary Kelly was last seen here before she was murdered by Jack the Ripper.

A relic of Victorian grandeur hides beneath a busy South London road.

A subterranean ice warehouse that has lain hidden beneath central London for over a century is now open to the public.

A 1,215-foot tunnel transports pedestrians beneath the River Thames.

This legendary city has been a tourist attraction for centuries.

A historic fort commemorating the United States' naval history.

A measuring mishap led to these artificial stone ladies losing their stomachs.

This 200-meter-high waterfall marks the site of Achilles’s immortal baptism at the mouth of the River Styx.

Τhis feline monument commemorates fallen soldiers on a field that saw many, many battles.

A discarded movie prop that was the original monolith for "2001: A Space Odyssey."