Europe's greatest museum is the Louvre in Paris. It was a thrill to take our Best of Europe in 21 Days tour group there to enjoy its unforgettable collection of paintings. Paris is relaxed in October. And -- even on the once-each-month free day, with heightened security and a sizable line -- we got the group inside with just a 20-minute wait. Just gathering our group under the iconic pyramid entrance was exciting. Experiencing the Mona Lisa is more than just seeing a famous painting.