Under Hanoi’s medieval citadel sits a secret military headquarters from the final years of the Vietnam War.

One of the most breathtaking railways in Europe also takes one of the steepest climbs, from fjord to mountain plateau.

This "preacher's pulpit" once used for pagan ritual, is home to a new, and dangerous ritual.

The Thai Army has dug deep trenches along the Thai/Myanmar border to prevent drug smuggling.

This mountain sunrise is one of the most breathtaking views in Thailand, yet well off the tourist trail.

The cursed island of black pebbles.

The great polar explorer is remembered in this far northern town, where he embarked on his final expedition.

A collection documenting Nazi occupation of Norway, including a painting believed to be made by Hitler.

Five soviet prisoners of war were executed at this spot just days before the liberation of Norway.

An impressive museum dedicated to the resource that made the Scandinavian country rich.

A little Lady Liberty stands in the Norway town where the copper for the real thing came from.

This striking landscape in northern Vietnam contains both geological and archaeological wonders.

The rusted hull of a WWII German destroyer pokes above the surface in a Norwegian fjord.

The last fully functional fortress of Germany's World War II Atlantikwall.

Housing the famous Norwegian ice-defying 19th century polar exploration ship.

Accessible only at low tide, the deserted island is dotted with World War II ruins.

The barrel-made lookout from Shackleton's final ship is tucked away in the crypt of one of London's oldest churches.

The oldest library in Scotland was built from the remains of a church to hold a churchman's library.

This gnarled old tree supposedly sprouted from seeds kept in the pocket of a 16th-century Spanish sailor.

This open-air museum was originally a World War II testing ground for German missiles and rockets.

This fairytale medieval church in Poland originally spent centuries in Norway.

Memorial to the lost dead of Gdansk, whose resting places were destroyed during World War II.

A memorial to the beloved brown bear that served in the Polish army during World War II.

What was once an underground Nazi city is now Europe's largest bat reserve.