Øer marina is a modern design, but constructed, very much like the Vikings would have built it.
The whole area around the harbor was filled with villages and shipdocks during the Viking age, and both Viking-ships and warrior-graves have been excavated from the area, but right next to this little water-paradise, across the Vig, lays a towering neighbor, with an amazing history. It is the holy mountain of the Elf-king (Ellemandsbjerget).
The belief in the Elfs and other land-spirits was very strong in the Viking age. The Elfs were believed to be a magical race that connected the world of man with the Gods of Asgaard and Vanaheim. Often they could cause danger to humans but if you made sure to bring sacrifices to them, they would instead help and guide you through life.
In heathen times people came to Ellemandsbjerget bringing offerings and performing rituals, like playing chants on their jaw-harps and offer food and mead, to the elf-king in the mountain. At the same time Ellemandsbjerget was used as the main beacon-fire for the fortress of Aros, so many people saw the mountain as a protector of the city, and made offerings to the holy hill.
This heathen tradition was so strong that it continued well into the christian era, and only when monks started spreading the rumor, that the Elf-king really was a demon that kidnapped young girls and dragged them underground, did the tradition slowly begin to die out.
Today you can easily go ashore and explore the mountain of the Elf-king, and if you’re brave, you can bring a small sacrifice to the king in the hill.