The Darvaza Gas Crater, famously nicknamed the “Door to Hell,” is one of Turkmenistan’s most extraordinary landmarks. Located deep in the Karakum Desert, this fiery pit has been burning continuously since the early 1970s, when Soviet engineers reportedly set fire to a collapsed natural gas field to prevent the spread of methane.

Potosí rises on the Altiplano of southern Bolivia and for centuries it was one of the richest cities in the world because of what lies just beyond its streets. At the foot of Cerro Rico (“Rich Mountain”), silver was discovered in the mid-1500s, and within a few decades the city became a center of mining and wealth that shaped global trade and economies.

Speyer, located in the Rhineland-Palatinate region of Germany, is a city rich in history and culture. One of its most notable landmarks is the Speyer Cathedral, a UNESCO World Heritage Site and one of the largest Romanesque churches in the world.

Brussels, the vibrant capital of Belgium, offers a perfect blend of medieval charm and modern sophistication. At its heart lies the iconic Grand Place, a UNESCO World Heritage Site known for its stunning Gothic and Baroque guildhalls.

Amsterdam, the 17th century capital of Holland, is often called the "Venice of the North" due to its numerous, boat-navigable canals. Truly rich in history, the oldest part of this populous, multicultural city is Sloten, which dates all the way back to the 9th century.