In the early 13th century, German knights returning from the crusades understood the potential wealth of the region, and hung around. They built their central castle on a hill overlooking the plain, 19km north of Brasov. A 4m thick wall, a moat and four towers (of which the western one is the oldest) were not enough to prevent the Mongols and Turks from destroying the castle, and after restorations an earthquake in 1838 did heavy damage. Since then, it has been in ruins. When the knights were kicked out of the country in 1225 by the Hungarian king, they moved to Prussia in Northern Europe, where they immediately built a new, grander castle, also called Marienburg (Malbork, see Gdánsk In Your Pocket). The unguarded ruins can be explored by foot and can also be admired from the left hand side of a train running from Brasov to Sighisoara.