RAF Tarrant Rushton dropped troops near Caen to begin Operation Tonga. Dorset experienced an increase in holiday-makers after the war. First popularised as a tourist destination by George III's frequent visits to Weymouth, the county's coastline, seaside resorts and its sparsely populated rural areas attract millions of visitors each year. With farming declining across the country, tourism has edged ahead as the primary revenue-earning sector. Settlements Dorset is largely rural with many small villages, few large towns and no cities. The only major urban area is the South East Dorset conurbation, which is situated at the south-eastern end of the county and is atypical of the county as a whole. It consists of the seaside resort of Bournemouth, the historic port and borough of Poole, the towns of Christchurch and Ferndown plus many surrounding villages. Bournemouth, the most populous town in the conurbation, was established in the Georgian era when sea bathing became popular. Poole, the second largest settlement (once the largest town in the county), adjoins Bournemouth to the west and contains the suburb of Sandbanks which has some of the highest land values by area in the world. The other two major settlements in the county are Dorchester, which has been the county town since at least 1305, and Weymouth, a major seaside resort since the 18th century. Blandford Forum, Sherborne, Gillingham, Shaftesbury and Sturminster Newton are historic market towns which serve the farms and villages of the Blackmore Vale in north Dorset. Beaminster and Bridport are situated in the west of the county; Verwood and the historic Saxon market towns of Wareham and Wimborne Minster are located to the east. Lyme Regis and Swanage are small coastal towns popular with tourists. Under construction on the western edge of Dorchester is the experimental new town of Poundbury commissioned and co-designed by Prince Charles. The suburb, which is expected to be fully completed by 2025, was designed to integrate residential and retail buildings and counter the growth of dormitory towns and car-oriented development. Physical geography Dorset covers an area of and contains considerable variety in its underlying geology, which is partly responsible for the diversity of landscape. A large percentage (66%) of the county comprises either chalk, clay or mixed sand and gravels. The remainder is less straightforward and includes Portland and Purbeck stone, other limestones, calcareous clays and shales. Portland and Purbeck stone are of national importance as