The medieval church of Saint-John-Baptist (Janskerk) will be the location of all plenary sessions of the Conference (except for the opening ceremony, which will be in the Dom Church). The church was founded by bishop Bernold c. 1040 AD as one of the five Utrecht collegiate churches in Utrecht, allegedly forming the ‘Utrecht cross of churches’. Originally, the church had two church towers, one of which was already torn down in the course of the 14th century due to construction problems. The second tower was torn down in 1682, together with a part of the west part of the church that was heavily damaged by the same tornado of 1674 that brought down part of the Dom Church (and damaged many other buildings in Utrecht).
In 1580, after the Reformation, public Roman-Catholic services were forbidden and the church was used by Walloon and English Protestant communities in Utrecht; the choir of the church was used as city library, later one as library of Utrecht University. In 1656, the church was formally handed over to the Dutch Reformed Church. After the university library moved to a new location in 1821, the church building was used for several non-ecclesiastical purposes, such as accommodation for Russian and Prussian soldiers (early 19th century) or as wood storage.
After decades of decay, the choir part of the church was restored during the renovation of 1947; in 1977-1981 a new belfry was built and the original 13th-centruy romanesque character of the nave was restored: the painted wooden ceiling still contains some parts from the original wooden ceiling. Currently, the building is owned by the Protestant Church of Utrecht (Protestantse Gemeente Utrecht) and used for both ecclesiastical and non-ecclestiastical events; every Sunday it is home to the weekly church services of the Oecumenical Student Community EUG (Oecumenische Studentengemeente EUG).