The Netherlands Fortress Museum in Naarden takes visitors back to a time when Naarden was a trading city and a military defence centre protecting Holland against her enemies. The museum tells visitors about the military history and development of Naarden, and talks about the battles that took place there. Visitors get a chance to explore the network of underground corridors that were so important to the defence of the country for hundreds of years, as well as the opportunity to take a boat trip through the fortress moat.