"Sure, you’ve seen old European churches before, but Cathédrale Notre-Dame de Strasbourg is truly a sight to behold. A prime example of Gothic architecture, the 466-foot-tall cathedral was actually the highest building in the world for more than 200 years, after its construction in the mid-17th century. Entry is free, so go in to admire the astronomical clock from 1843, adorned with hand-carved figurines."