Bornholm is a Danish island in the Baltic Sea that is 135 km or 83 miles east of Denmark, 37 km or 22 miles south of Sweden, 90 km or 55 miles north of Poland and about 90 km or 55 miles northeast of Germany. That advantageous location has made it appealing to many over the years including the Templars. The Templars built four churches on the island at Nyker, Nylars, Olsker and Østerlars.
The Danish Archbishop Eskil had stayed at the monastary Clairvaux from 1161 to 1167. The monastary was founded by Bernard of Clairvaux who was the nephew of one of the founding Knights Templar Andre de Montbard. Eskil and Templar Grand Master Bertrand de Blanchfort made a plan about 1164 to build storage stores on Bornholm to house supplies for the fleets carrying out the Crusades in the Baltics. The church at Østerlars was the first constructed and all four had the distinctive Templar architecture design and are referred to as round churches. The distance between the Østerlars and Nylars churches was the exact same distance as that between Østerlars and another church in Rutsker, That distance is 14,336 meters or 47,034 feet. There is some speculation that the Templars had hidden treasure from the Crusades at the churches.
Knights Templar page