If you're heading to Paris for a few days, I highly recommend a visit to the Chateau de Versailles just out of Paris. You'll need to allow at least half a day (a full day, if possible) but it is worth it just to admire the gardens and palace built for Louis XIV, the Sun King, from 1668.
To reach Versailles on a day trip from Paris you can either do a tour by coach or catch the RER train, line C. (Buy a "Paris - Versailles Rive Gauche" ticket, zones 1-4.) The journey time by train is around 45 minutes and the Palace is within easy walking distance from Versailles station.
If you plan on visiting the Palace interior, I recommend arriving early as the queues to enter can be particuarly long, especially in Summer. It's also a good idea to join a small group tour which includes skip the line admission tickets. Not only will you save time, you're knowledgeable guide will help you to learn more about this impressive palace. Click here to check details and prices.
Highlights of the Palace include the Hall of Mirrors, the Chapelle Royale and the Salon de Venus. You'll also see an abundance of priceless artworks including paintings, sculptures, furniture and statues.
Even if you're not usually into gardens, the endless gardens, fountains, ponds and statues at the Palace of Versailles are sure to blow you away.
Louis spared no expense when having his palace designed and built and whilst it really is quite ostentatious, it is impressive.
Allow plenty of time to wander the gardens - or hire a golf buggy if you're short on time or not fond of walking too far. A visit to the Grand Trianon and the Petit Trianon at the far end of the gardens is worthwhile, and don't forget to take some time out to sit and absorb the beauty around you. It really is superb.