21. Prague, Czech Republic
Source: Iconosquare
One of the richest cities in terms of historical value, it’s no wonder Prague is one of the most popular destinations. It’s the capital of the city and the 15th largest in the European Union. It is home to about 1.24 million people. Many come for the Prague Castle or the historic city center, which is a UNESCO World Heritage site. It is home to 10 museums, numerous historical exhibits and some of the world’s most well known theaters. It had about 6.2 million visitors in 2013.