Described by UNESCO as a masterpiece of Gothic architecture, the Cologne Cathedral or the Kölner Dom is an awe-inspiring world heritage site. The construction of this Gothic cathedral started in 1248 and took 632 years to complete. When the church was finally completed in 1880, it was one of the world's tallest buildings. The Dom stands an imposing 157 meters (505 feet) high and while climbing one of the towers may be quite an endeavor, the view from the top is definitely worth the effort. Located within the cathedral is the Treasure Chamber, which is home to significant religious artifacts, including the hooked staff of Saint Peter. The Cologne Cathedral is a well-known historic landmark that can't be missed.