Complex sentence: Caves are a theme on many Olmec-style monuments: several Olmec "altars" depict shamans or rulers emerging from caves, and several monuments at the archaeological site of Chalcatzingo, to the north, also feature cave motifs.
Split into simpler sentences: Caves are a theme on many Olmec-style monuments. Several Olmec "altars" depict shamans or rulers emerging from caves, and several monuments at the archaeological site of Chalcatzingo, to the north, also feature cave motifs.