Poole Harbour is a large natural harbour in Dorset, southern England, with the town of Poole on its shores. The harbour is a drowned valley formed at the end of the last ice age and is the estuary of several rivers, the largest being the Frome. Famous for its impressively large harbour, Poole has served as an important trading seaport throughout the years and was also a major departing point for the Normandy landings. Today, the town is quietly pleasant during the winter months and really comes to life in the summer.