5 buildings you probably didn't know took more than 500 years to construct

Not only is it the tallest church tower in the world, but it was financed entirely by local residents - which is probably why it took more than half a millennium to build. The mother of all crowdfunding projects was prone to running out of money. Finally completed in 1890, the Ulm Cathedral is the hallmark of the southern German city of Ulm and Germany's largest Protestant church.

The largest brick building in Europe, the castle in Malbork took more than 700 years to complete due to ongoing structural changes, but also because of war and pillaging. Most recently, more than half of the complex was destroyed at the end of World War II. Today, Malbork Castle is protected as a UNESCO World Heritage Site and is one of the most important tourist sights in Poland.

Johann Wolfgang von Goethe was one of the biggest fans of the Strasbourg Cathedral. At the time of his studies there in the early 1770s, it was the tallest church in the world, measuring 142 meters (466 feet). However, construction continued at the site for another 100 years. It was left unfinished in 1970, with the south tower missing to this day.

The Kremlin in Moscow, known for its red bricks, took more than 800 years to complete. Located at the heart of the city, the building complex served as the residence of the czar and his family mainly in the 16th and 17th centuries before becoming the seat of government during the Soviet era. Nowadays it mainly houses museums and is protected as a UNESCO World Heritage Site.

Wawel in Krakow, Poland, takes the gold medal, looking back at a building history of more than 1,000 years. The complex used to be the residence of Polish kings, with its beginnings dating back to the 10th century. With ever more edifices added to the installation over the centuries, Wawel truly became a never-ending story, with the most recent remodeling dating back to the last century.