Looking at a map of Europe, you might notice something unusual sandwiched between Poland, Lithuania, and the coastline of the Baltic Sea. It’s a small slice of Russia, completely cut off from her motherland by several hundred miles, and it’s called Kaliningrad.

Kaliningrad is an obscure Russian exclave surrounded by members of the European Union, a remnant of the time when the Baltic states separated from the former Soviet Union. Remarkably, it remains largely unknown elsewhere in Europe and the United States.

Technically, Kaliningrad is an “oblast,” or state, and part of the Russian Federation despite being geographically separated from it. It’s home to around 900,000 Russians, many of whom live in the largely grim concrete capital city, also called Kaliningrad.

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For centuries, this coastal city had a rich historical heritage under a much different name. Kaliningrad—named for Mikhail Kalinin, Chairman of the Soviet Presidium under Stalin—was once Königsberg, the capital of Prussia. Founded by the original Teutonic Knights in 1255, it flourished as a trading port and guild city that was part of the influential North German trading organization the Hanseatic League. Königsberg was also the birthplace, in 1724, of the philosopher Immanuel Kant, who lived almost his entire life there. It was a city of universities, castles, cathedrals, and bridges.

Library of Congress via Wikimedia // Public Domain

Most of Königsberg’s rich culture was all but destroyed during World War II. The city was heavily bombed by the Royal Air Force, with the ruins seized by the Red Army in April 1945. The remaining German population either fled or was expelled by force, the city renamed, and much of its heritage concreted over. Today the capital is characterized by drab concrete tower blocks and a high unemployment rate.

The sad story of Königsberg’s destruction is best summed up by the construction of the House of the Soviets. A particularly imposing example of brutalist Soviet architecture, it was designed in 1960 to be the central administration center of the Kaliningrad Oblast. It was built upon the ruins of Königsberg castle: Rather than preserve what they saw as a “center of fascism,” the Soviets blew up the old fortress of the Grandmasters of the Teutonic Order. Nicknamed the “buried robot” by locals due to its resemblance to a giant concrete robot’s head, the building was never finished. Construction stopped in the 1980s, as the robot head began to sink into the ground. The ancient subterranean tunnels under the old castle also began to give way, in what became known as the “revenge of the Prussians.” The exterior was finally finished in 2005, in time for a visit from President Putin, but the inside remains empty and unfinished.

The House of the Soviets. Image credit: Volkov Vitaly via Wikimedia // CC BY 1.0

The foundation of the House of the Soviets is also rumored to be the last resting place of the infamous Amber Room, one of the great lost works of World War II. Constructed by the Prussians as a gift to Peter the Great, this dazzling chamber of gold and amber panels, once considered the “eighth wonder of the world,” was installed at the Russian Imperial Catherine Palace near St. Petersburg. After the Nazi invasion in World War II, the priceless room was dismantled by the Germans and sent to Königsberg for display in the old Teutonic Castle, whereupon it was never seen again after the castle was bombed. Whether it remains buried under the rubble of the old castle, or whether it was stolen, is one of the great mysteries of the war.

The Soviet army attacks Königsberg in April 1945. Image credit: Getty Images

While Kaliningrad isn’t well-known in the United States, it is firmly in the minds of the Russian government and NATO. As Russia’s only European port that remains ice-free all year long, the oblast is currently home to the imposing Baltic Fleet, the Russian Navy’s presence in the Baltic Sea (Crimea is also ice-free, but the geopolitical situation there is rather complicated). It has also seen vast amounts of troops and weapons poured into the region, to the increasing alarm of the West. Dmitry Gorenburg, an expert on the Russian military with the Center for Naval Analyses in Arlington, Virginia, told Radio Free Europe that Kaliningrad is the “obvious place” to build up military hardware: “It's almost like you can set it up as a forward-operating base without leaving your own country’s territory.”

Today, Kaliningrad remains an obscure part of Europe that speaks to the carving up of centuries of history that followed World War II. Its dull concrete hides what was once a beautiful medieval city—and may also be hiding the missing eighth wonder of the world.