Over Teplice Castle square is the Cathedral of St. John the Baptist, which was built in 1585 on the ruins of an ancient building, which served for the celebration of worship. Its bell tower were erected in 1594, but only after 50 years, the Western tower was damaged by lightning. Because of the fire all the bells fell into disrepair. In 1659 the Church of St. John the Baptist brought three new bells, which were cast mikuláš lion. Two of them survived until our days. One is still used in the Church, and the other was transported to Prague. The fate of the third is unknown.

In the early eighteenth century facade of the Church was remodelled in Baroque style. The furniture, which now can be seen in the interior of the Church, circa 1730. The image of St. John the Baptist, which can be seen on the main altar and side altars, was created by Czech painter Peter Brandl. Also there kept painting made by the artist Vaclovas Rainer.

In the crypt of the Church of St. John the Baptist are the tombs of two famous noble families in Bohemia – Whisky and clari-Aldringen, whose life was closely connected with Greenhouse.

At the moment the Church of St. John the Baptist is valid, but the building is also used for concerts of symphonic music. Great acoustics allows you to turn a simple melody into the divine, so the local musical performances are very popular as the Greenhouse citizens and visitors of this resort.