 Approximately 1,100 of the 2,000 Birka graves have been excavated.The archaeological finds from the excavations are held by Swedish Museum of National Antiquities in Stockholm.In 1834, a thousand years after Ansgar visited the island, the so-called "Ansgar Cross" was erected at "Borgberget", and a hundred years later the "Ansgar Chapel" was built just east of the village.