Watford is a commuter town at the northwestern edge of Greater London, sitting just inside Hertfordshire. It has the busy, practical character of a place that serves a large surrounding population, with a pedestrianized High Street and the intu Watford shopping center drawing people from across the county. Watford FC, the local football club, provides much of the town's identity, and catching a match at Vicarage Road is the most authentic local experience you can have.
The real draw for most visitors is the Warner Bros. Studio Tour London, located at the Leavesden Studios just outside town. The "Making of Harry Potter" experience is one of the most popular tourist attractions in England, and you will need to book well in advance. The tour is genuinely impressive even if you are not a devoted fan, with full-scale sets, costumes, and special effects exhibits spread across two enormous soundstages.
Beyond the studios, Watford is a pleasant enough place to spend an afternoon. Cassiobury Park, the town's main green space, follows the River Gade and has a miniature railway, paddling pools, and mature woodland that hints at the estate that once stood here.