The Postal Museum in London is a hidden gem that brings over 500 years of communication history to life. Located near King's Cross, it’s a family-friendly spot where you can explore everything from antique postboxes and early Christmas cards to millions of stamps and wartime mail. The real highlight? A ride on Mail Rail, London's secret underground railway that once transported mail across the city. This 20-minute journey takes you through restored tunnels and stations, offering a fascinating glimpse into the past.