Felsenburg castle was probably built in the 12th century for the Freiherr of Kien. The castle was built on a rocky spire above the road over the Gemmi pass into Valais. It was inherited, along with the rest of the Herrschaft of Frutigen, by the Freiherr of Wädenswil in 1290. The Freiherr of Turn acquired it from Wädenswil in 1312. It was mentioned in a record in 1339 as the castrum de Petra. It was again mentioned in 1368 as Stein, German for Stone. In 1400, Bern acquired the castle along with the rest of the Herrschaft. They abandoned Felsenburg and allowed it fall into ruin.
Currently, only the rectangular main tower and remnants of the outer walls are still standing.
References:The stone church of Gamla Uppsala, built over the pagan temple, dates from the early 12th century. Due to fire and renovations, the present church is only a remnant of the original cathedral.
Before the arrival of Christianity in Sweden, Gamla Uppsala was the seat of Swedish kings and a ceremonial site known all over northern Europe. The settlement was home to royal palaces, a royal burial ground, and a great pagan temple. The Uppsala temple, which was described in detail by Adam of Bremen in the 1070s, housed wooden statues of the Norse gods Odin, Thor and Freyr. A golden chain hung across its gables and the inside was richly decorated with gold. The temple had priests, who sacrificed to the gods according to the needs of the people.
The first Christian cathedral was probably built in the 11th century, but finished in the 12th century. The stone building may have been preceded by a wooden church and probably by the large pagan temple.