The Rotunda is built around a 17th-century church that was too small for the community's needs, and this more recent structure can seat around three times the village's population. The austere interior impresses through sheer size. Paintings of scenes from the life of St John the Baptist adorn the six side chapels. To the left of the altar is a museum displaying baroque sculptures and relics from the old church. Work on the church began in 1951 and was completed in 1971.

It was built mainly with the volunteer labour of parishioners and paid for by local donations. A small lift (€3) takes visitors up to the gallery surrounding the dome, for great panoramas – the 74m dome is higher than St Paul's Cathedral in London.