Princess Kate Middleton and her daughter, Princess Charlotte, hopped aboard London’s Underground for a rare outing. Kate, 44, and Charlotte, 11, were seen mingling with commuters while riding the Elizabeth Line, which travels from Greater London to parts of Buckinghamshire, Essex and Hertfordshire. “They spoke to members of the public sitting across from them,” a source told Hello! after riders spotted the duo during a public transit adventure on Saturday, October 10. “They had security with them. The security didn’t make it obvious they were there and they tried to make it...