Trecastagni, located at the feet of the Etna volcano, was inhabited since the Greek and Roman period, as many remains found in "Mulino" area testified. According to the tradition, its name derives from the three brothers and martyrs Alfio, Filadelfo and Cirino called "tres casti agni" (the three chaste lambs).
The Mother Church, featuring a striking contrast between its lava black columns and its white walls, is one of the most interesting building of the town. Noteworthy is also the Church dedicated to the Madonna della Misericordia, also called "del Bianco", the Chiesa di S. Antonio, and the Sanctuary of the three Martyr Saints.