Mulberry Harbour Phoenix Units, Portland

The Phoenix breakwaters were a set of reinforced concrete caissons built as part of the artificial Mulberry harbours that were assembled as part of the preparations for the Normandy landings during World War II. They were constructed by civil engineering contractors around the coast of Britain. They were collected at Dungeness and Selsey, and then towed by tugboats across the English Channel and sunk to form the Mulberry harbour breakwaters replacing the initial "Gooseberry" block ships. Caissons were added in the autumn of 1944 to reinforce the existing structure to cope with the harbour continuing in use longer than planned. Several Phoenix breakwaters still exist in Britain: two are part of the harbour off Castletown at Portland Harbour in Dorset, and two can be dived in less than 10 metres of water off Pagham in West Sussex. There is also a smaller Phoenix Caisson (type C) in Langstone Harbour in Hampshire.A wrecked Phoenix breakwater is also to be seen, broken in two, in the Thames estuary off Shoeburyness in Essex. It broke while being towed from Harwich in June 1944. To avoid it causing a hazard to shipping in the Thames estuary, it was beached on the mud on the northern edge of the Thames dredged shipping channel. It is about a mile from the beach. It is not quite covered at high tide, but it is topped by a beacon to warn shipping of its presence. Several Phoenix breakwaters were used in the Netherlands to plug gaps in the dykes, four of them for a dyke at Ouwerkerk after the North Sea Flood of 1 February 1953. These four have now been converted into a museum for the floods called the Watersnoodmuseum. One can walk through the four caissons. Two of the Phoenix breakwaters were sold to Sweden in 1949, initially towed to Frihamnen port in Stockholm and moved on 20 September 1956 to the newly-built heat and power plant in Hässelby where they remain as of 2021.

Castletown is a small village in Underhill on the Isle of Portland in Dorset. It is located close to Fortuneswell, on the shores of Portland Harbour, and includes a sandy beach, as well as one of Portland's notable highlights; Portland Castle, while the Weymouth and Portland National Sailing Academy is also located nearby. As with the rest of Portland's villages and settlements, Castletown has been designated as a conservation area, as it is a place of special architectural and historic interest. Underhill, incorporating Castletown and other settlements became designated in 1976 with boundary extensions in 1997 and 2000.

Portland Castle is an artillery fort constructed by Henry VIII on the Isle of Portland, Dorset, between 1539 and 1541. It formed part of the King's Device programme to protect against invasion from France and the Holy Roman Empire, and defended the Portland Roads anchorage. The fan-shaped castle was built from Portland stone, with a curved central tower and a gun battery, flanked by two angular wings. Shortly after its construction it was armed with eleven artillery pieces, intended for use against enemy shipping, operating in partnership with its sister castle of Sandsfoot on the other side of the anchorage. During the English Civil War, Portland was taken by the Royalist supporters of King Charles I, and then survived two sieges before finally surrendering to Parliament in 1646. Portland continued in use as a fort until the end of the Napoleonic Wars in 1815, when it was converted into a private house. Fresh concerns over invasion led to the War Office taking it over once again in 1869, but the castle was not rearmed and was instead formed accommodation for more modern neighbouring fortifications. During the First and Second World Wars it was used as offices, accommodation and as an ordnance store. In 1949, the War Office relinquished control, and in 1955 it was opened to the public by the state. In the 21st century it is managed by English Heritage and operated as a tourist attraction, receiving 22,207 visitors in 2010. Historic England consider the castle to form "one of the best preserved and best known examples" of King Henry's forts.

The Portland Royal Naval Hospital was a naval hospital on the Isle of Portland, Dorset, England. Serving HMNB Portland at Portland Harbour, the hospital is located close to Castletown. Discounting earlier, temporary incarnations of the hospital, the permanent naval hospital was built at the beginning of the 20th century. It closed in 1957, when it was handed over to the National Health Service, which still runs the hospital as NHS Portland Community Hospital.

Merchant's Railway was a horse drawn and cable operated incline railway on the Isle of Portland, Dorset, England, built for the stone trade on the island. It was the earliest railway in Dorset, opening in 1826. The railway ran two miles from many working quarries at the north of Tophill, along the edge of Verne Hill, to a pier at Castletown, from where the Portland stone was shipped. It was in operation from 1826 to 1939. Since becoming disused the original path of the railway has become a popular public footpath.

Bibby Stockholm, an engineless barge, is an accommodation vessel owned by the shipping and marine operations company Bibby Line.

HMP Weare was an Adult Male/Category C prison ship berthed in Portland Harbour in Dorset, England. It was the latest in a lengthy history of British prison ships, which included HMS Maidstone, used as a prison during Operation Demetrius in the 1970s, HMS Argenta, in use as a prison in the 1920s, and a long list of British prison hulks dating from the late 18th-century to the mid 19th-century.

RNAS Portland was an air station of the Royal Navy from 1917. The site was first built in 1917 as HMS Sarepta within the confines of Portland Harbour as a seaplane base; the aircraft operating from the base's slipways. In 1959 it became RNAS Portland (HMS Osprey)

RNAS Portland (ICAO: EGDP) was an air station of the Royal Navy, situated at the Isle of Portland, Dorset, England. It was established in 1917 on the western edge of Portland Harbour as HMS Sarepta. From 1959 the station shared the name HMS Osprey, the anti-submarine establishment based at Portland, with helicopters used for research and development in anti-submarine techniques. RNAS Portland remained operational until 1999.

Royal Naval Cemetery (once known as Naval and Military Cemetery) is a cemetery on the Isle of Portland, Dorset, England. The site overlooks Portland Harbour, and is found below the main entrance to the Verne Citadel (HM Prison The Verne). As the name suggests, the graveyard holds deceased servicemen and officers of Portland's Royal Navy which was stationed at the island until 1995. The cemetery holds 140 identified casualties in total to date, and is owned by the Ministry of Defence. The cemetery was first laid out during the 19th century. With the establishment of a naval base at Portland Harbour, and the Verne Citadel fortification, a number of fatalities began to occur. Burials of World War I (1914–1918) total 65, where 5 remain unidentified. The majority of World War II (1939–1945) graves are together in the Church of England section, near the Cross of Sacrifice. Of the buried, 10 are unidentified, whilst there are burials for 1 Norwegian Merchant Navy seaman and 12 German airmen. The cemetery remains well looked after to date and features a small amount of newer burials of recently deceased servicemen.

HMS Delight was a D-class destroyer built for the Royal Navy in the early 1930s. Delight was initially assigned to the Mediterranean Fleet before she was transferred to the China Station in early 1935. She was temporarily deployed in the Red Sea during late 1935 during the Abyssinia Crisis, before returning to her duty station where she remained until mid-1939. Delight was transferred back to the Mediterranean Fleet just before the Second World War began in September 1939. She served with the Home Fleet during the Norwegian Campaign. The ship was sunk by German dive-bombers on 29 July 1940 while attempting to transit the English Channel in daylight.

Royal Manor Theatre is a theatre located in Fortuneswell, Isle of Portland, Dorset, England. Formerly a Methodist chapel, the building was later converted into the Royal Manor Theatre, which opened in 1978.