The Oude Kerk is the oldest building in Amsterdam, and its floor is made of more than two thousand gravestones laid flat. Around sixty thousand people were buried under it before the city closed the church to burials in 1865, and Rembrandt's wife Saskia lies under one stone in a side chapel. Inside, the church is bright and largely empty, with a barrel vault of oak overhead that has been in place since about 1390.
The church was consecrated in 1306, changed religion once, and never quite got over it. Guilds and wealthy families bought side chapels and bolted them onto it, so the plan sprawls. Then the city changed sides in the Dutch Revolt, and the Protestants stripped out the altars and the statues and painted the vaults grey. Look up, because that grey is the reason anything survived: the medieval painting under it came through, and was uncovered in 1951. Services are still held on Sunday mornings. The rest of the week the church commissions new art, so one large installation usually fills the nave for months and the inside changes from one year to the next.