The Twin Mounds are a large pair of mounds at the south end of the Grand Plaza opposite Monks Mound, probably forming a mortuary complex although no excavations have been made into them. A building on top of the flat-topped mound, 60 or Fox Mound, may have served as a charnel house where bodies of important people were prepared for burial, and they may perhaps have been buried in the adjacent conical mound, 59 or Roundtop Mound. Soil corings around the mounds also suggest that they were built up on a shared platform.