The Planetarium in Franeker is the oldest working planetarium in the world. It was built by a local woolcomber, Eise Eisinga, after a local paper predicted the end of the world following a conjunction of Mercury, Venus and Mars in 1774. It took Eisinga 7 years to build the planetarium, which contained 10,000 hand-forged nails and uses a pendulum clock and 9 weights to control the planets. The planetarium now also holds and extensive collection of historic astronomical instruments.
