To fully explore the Tower of London, you should allow at least 3 hours. This will give you time to take a guided tour, see the Crown Jewels and learn about the history of the Tower. The British Museum is a huge collection with more than 8 million artifacts, and it is recommended to plan several hours to get the most out of your visit. Plan at least 2 to 3 hours to see the museum's most popular exhibits, such as the Rosetta Stone and the Egyptian mummies.