Costa Rica’s Underground [google_map_easy id=”25″] Location: Cote Lake Costa Rica Functions: Unknown Levels: Unknown Tunnels to: Unknown Notes: Extremely deep, and there have been numerous other reports of unknown submersible craft entering and leaving it. Local fishermen, out on the lake in the small hours, have seen various objects below them, giving off colored lights. Source: Location: Costa Rica Functions: Unknown Levels: Unknown Tunnels to: Unknown Notes: Source: