Oslo

In 1174, Hovedøya Abbey was built. The churches and abbeys became major owners of large tracts of land, which proved important for the city's economic development, especially before the Black Death.

Over the years, fire destroyed major parts of the city many times, as many of the city's buildings were built entirely of wood. After the last fire in 1624, which lasted for three days, Christian IV of Denmark decided that the old city should not be rebuilt again. His men built a network of roads in Akershagen near Akershus Castle. He demanded that all citizens should move their shops and workplaces to the newly built city Christiania, named as an honor to the king.

In the 18th century, after the Great Northern War, the city's economy boomed with shipbuilding and trade. The strong economy transformed Christiania into a trading port.

A map of the urban areas of Oslo in 2005. The grey area in the middle indicates Oslo's city centre.

Oslo has many parks and green areas within the city core, as well as outside it.

The lake's altitude above sea level is 183 metres. The water is in a popular hiking area. Near the water itself, it is great for barbecues, swimming, beach volleyball and other activities.