Hervormde Kerk - Wiuwert, Friesland, Netherlands
Home of the Preserved Mummies of the Hervormde Kerk.
From Atlas Obscura: "A bizarre form of natural mummification was discovered in the church of this Frisian village. In 1765 carpenters were working in the church of the small village of Wieuwerd, Friesland, when they found a crypt with 11 coffins that looked as if they were brand new.
To their astonishment the bodies inside the coffins showed no signs of decay. The cool, dry atmosphere of the church had apparently caused decomposition to slow to a glacial pace (though it did not stop completely). Birds that died in the crypt became mummified too.
Of the 11 mummies, four remain today. It is believed that they belonged to the Labadist, a protestant religious movement of the 17th century."