Church of Sts Peter and Paul, Gothic church in Mělník, Czech Republic

The Church of Sts Peter and Paul is a Gothic church beside Mělník Castle, with a 65.87-metre square tower topped by a Baroque onion dome above the Elbe–Vltava confluence. Its hall interior measures 40 by 21.5 metres, with three equal-height naves carried on six columns and a net-ribbed vault in the presbytery.

The church traces its origins to around the year 1000, when it was founded under the patronage of Princess Emma. It was rebuilt and expanded over several centuries, reaching roughly its current form around 1520.

The parish holds the status of a proboštství, recalling the collegiate chapter that existed here from the early 11th century until 1421. The church is dedicated to Saints Peter and Paul, and its main altar painting of the two apostles is attributed to Karel Škréta. A side altar from 1697 by Filip Mazanec shows St Ludmila with the child St Wenceslas and a panorama of Mělník in the background.

The church stands next to Mělník Castle above the confluence of the Elbe and Vltava. The ossuary in the crypt under the presbytery holds bones arranged into an anchor, a cross and a heart; it was walled up after 1787 and rearranged by anthropologist Jindřich Matiegka in the early 20th century.

The crypt beneath the church holds the bones of around 15,000 people, arranged along the walls in patterns of anchors, hearts, and crosses. This way of displaying human remains was once a way of honoring the dead and is rarely seen in this region.