The Church of St. Elijah is located on the top of Ilija hill (Ilijina glavica) in the village of Mesari, north of the main road Trebinje – Mostar. It is located on the edge of Popovo polje, 20 km west of Trebinje. The Church of St. Elijah is a trikonchos, which has been rebuilt several times. The last time, according to the inscription on the architrave beam, was in 1897. This church has a pre-Romanesque stylistic character, and it is considered that the original church was probably built in the period from the 9th to the 11th century. It is among the oldest buildings in Herzegovina. The Church of St. Elijah with a prehistoric burial mound (tumulus) and a necropolis with stećci in Mesari was declared a national monument of Bosnia and Herzegovina in 2008.