The fortified church was built in the 13th century and has been a UNESCO World Heritage Site since 1999. When I was there, it was closed. If you want to visit it, you have to call a specific phone number. I found the following numbers online: Tel.: +40/258/747 220 and Tel.: +40/740/234 297. I didn't try them myself, though, because I was passing by on Whitsun Sunday.