Of course you must visit Versailles! Use the app Rome2Rio to make sure you get here safely and on time, as there are many routes and the train does split. Here at Versailles, you visit the castle, and you do it early or there will be a massive crowd. You could also visit the place after 3-4 PM to avoid the crowd. Guess who used to hang out here? Marie Antoinette! You can visit her hamlet. Also, it was the seat of power when Louis XIV moved from Paris, until the French Revolution in 1789. Versailles is of great historic importance, and its brilliance comes alive through its opulence and grandiose.