This historic city dates back to 10 B.C. From 1949 until 1990, it was the capital of the former West Germany. It is the birthplace of the famous composer Ludwig van Beethoven, whose original home is now a museum. Budding with all types of exotic plants and flowers is Bonn's famous 400 year-old Botanischer Garden. (PRISMA BILDAGENTUR AG/ALAMY)