During her reign, Queen Elizabeth II of England has met 10 sitting US Presidents, every one from Eisenhower to Obama except for Lyndon Johnson. She also met Harry Truman as a princess in 1951 and former President Herbert Hoover in 1957.
You can see the entire progression here or here. QEII is more definitely a human wormhole.
BTW, Elizabeth is creeping up on Queen Victoria as the longest-reigning British monarch, just another two-and-a-half years to catch her. Victoria reigned during the terms of 19 different Presidents but never met any of them and had an unfair advantage...lots of short terms and one-term Presidencies back then. (via mlkshk)