View of Viðey House, Viðey Island

The island of Viðey, with a surface of 1.7 square kilometers, is the largest of the islands in the Kollafjörður before Reykjavík. It originated from a volcano, which was heavily eroded and flattened during the Ice Age. At the end of the Ice Age, the sea level rose and only about 9000 years ago, the sea level had dropped so low that Viðey rose from the sea and plants could gain a foothold. The island is completely covered by vegetation, partly by grass, partly by marsh plants. It offers nesting opportunities for many species of birds, but especially for eider ducks.
Viðey has been inhabited since the 10th century. From 1225 to 1539 there was a monastery on the island, probably founded on the initiative of the poet Snorri Sturluson. In the course of the Reformation, the last Catholic bishop of Iceland conquered Viðey in 1550 and restored the monastery. But in the same year, after the violent death of Bishop Jón Arason, the monastery was finally dissolved. Later, Viðey became the official residence of the royal treasurer. For him, the manor Viðeyarstofa was built in 1755, Iceland's first stone house. The island church was inaugurated in 1774. After the island was abandoned in 1959 by the last inhabitants, the city of Reykjavík restored the manor house and used it since 1988 as an inn and for conferences. By the way there is a ferry service to the island from Reykjavík and especially in the summer months Viðey is attractive as a hiking area.

I have a fascinating view here on Videy