4 Best Sights in St. Albans, The Thames Valley

Attention all Muggles—this spectacular attraction just outside Watford immerses you in the magical world of Harry Potter for hours. From the Great Hall of Hogwarts, faithfully re-created, down to the finest detail, to "magical" paraphernalia beautifully displayed in the vast studio space, each section of this attraction showcases the real sets, props, and special effects used in the eight movies.

After entering the Great Hall, a fitting stage for costumes from each Hogwarts house, you can admire the intricacies of the huge Hogwarts Castle model, ride a broomstick, try butterbeer, explore the Forbidden Forest, and gaze through the shop windows of Diagon Alley. The Hogwarts Express section—at a faithfully reproduced Platform 9¾—allows you to walk through a carriage of the actual steam train and see what it's like to ride with Harry and the gang.

Tickets, pegged to a 30-minute arrival time slot, must be prebooked online. Slots fill up fast over summer and school holidays, so reserve well in advance. The attraction is a 20-minute drive from St. Albans. You can also get here by taking a 20-minute train ride from London's Euston station to Watford Junction, then a 15-minute shuttle-bus ride, free with a valid Studio Tour ticket; the shuttle runs every 30 minutes. Via car from London, use M1 and M25. Parking is free.

Your imagination can take you back to AD 130 as you walk around the ruins of this 2,000-seat Roman Theater, one of the few in the country. Next to it are the scant ruins of a Roman town house, shops, and a shrine. Believed to be the "oldest producing theatre" in the U.K., you can catch shows here throughout the year.

With exhibits on everything from food to burial practices, the Verulamium Museum, on the site of the ancient Roman city, explores life 2,000 years ago. The re-created Roman rooms contain colorful mosaics that are some of the finest in Britain. Every second weekend of the month, "Roman soldiers" invade the museum and demonstrate the skills of the Imperial Army.

Adjacent to the Verulamium Museum, this park contains the usual—playground, wading pool, lake—and the unusual, namely Roman ruins that include part of the town hall and a hypocaust, or central-heating system, that dates from AD 200 and included one of the first heated floors in Britain. Brick columns supported the floor, and hot air from a nearby fire was drawn underneath it to keep bathers warm.