Knaresborough is a small market town perched on and around a steep sided gorge on the fringe of the North York Moors. It is best seen from the inside of a train, travelling over the huge viaduct that spans the River Nidd, just before you arrive in the quaint Victorian station. That was my first view anyway, and I've never found one to match it.
Knaresborough is a historic town mentioned in the Doomsday book, and boasts such ancient treasures as Knaresborough Castle and the more dubious Mother Shipton's Cave. The gorge itself is stunning all year round, be it when the river is in flood in the Winter, or when the trees on its flanks turn to gold in the Autumn. My favourite acitivities in Knaresborough include visiting the numerous tea rooms, and going boating on the river in the Summer. Boat hire is extremely cheap if there's a group of you, and though the area to row on is limited to a few hundred meters, the distance between the two bridges that span the Nidd offer a perfect amature race course ;o)
Knaresborough is also the home of 'Ye Olde Chymists', the oldest Chemists in all of England. It is now an extremely well stocked sweet shop that everyone should visit, and is a wonderful piece of Medieval architecture. On Wednesdays Knaresborough hosts a farmer's market which it's worth timing your visit to coincide with, and on the 2nd Saturday of June (although I have never experienced it) hosts the infamous Knaresborough Bed Race. (The bed race involves various volunteers from local groups jumping onto a hospital bed and being pushed around the town, down an extremely steep hill and across the river to raise money for charity).
Knaresborough has an extremely detailed website at http://www.knaresborough.co.uk and is a very pleasant day trip if you're in the area.