There has been a castle at Glenarm since the 13th century, where it resides at the heart of one of Northern Ireland's oldest estates. The present castle was built by Sir Randal MacDonnell, 1st Earl of Antrim, in 1636, and it has remained in the family since its construction. It is currently owned by Randal, Viscount Dunluce, the son of Alexander McDonnell, 9th Earl of Antrim. The McDonnells have been in Glenarm for nearly 600 years and the Estate has been in the family for 400 years.
The Castle's Walled Garden is open to the public between May and September and hosts many events.
References:Varberg Fortress was built in 1287-1300 by count Jacob Nielsen as protection against his Danish king, who had declared him an outlaw after the murder of King Eric V of Denmark. Jacob had close connections with king Eric II of Norway and as a result got substantial Norwegian assistance with the construction. The fortress, as well as half the county, became Norwegian in 1305.
King Eric's grand daughter, Ingeborg Håkansdotter, inherited the area from her father, King Haakon V of Norway. She and her husband, Eric, Duke of Södermanland, established a semi-independent state out of their Norwegian, Swedish and Danish counties until the death of Erik. They spent considerable time at the fortress. Their son, King Magnus IV of Sweden (Magnus VII of Norway), spent much time at the fortress as well.
The fortress was augmented during the late 16th and early 17th century on order by King Christian IV of Denmark. However, after the Treaty of Brömsebro in 1645 the fortress became Swedish. It was used as a military installation until 1830 and as a prison from the end of the 17th Century until 1931.
It is currently used as a museum and bed and breakfast as well as private accommodation. The moat of the fortress is said to be inhabited by a small lake monster. In August 2006, a couple of witnesses claimed to have seen the monster emerge from the dark water and devour a duck. The creature is described as brown, hairless and with a 40 cm long tail.