Actun Tunichil Muknal (ATM) is renowned as one of the most remarkable Maya ceremonial caverns discovered to date. In active use during the early classic era around 300-600AD, a tour of the ATM involves navigating through an underground river, surmounting and ducking beneath a multitude of rocks, eventually leading to the main chamber.

The intrinsic attribute of the ATM cave lies in its wet nature – the entrance requires a swim, followed by wading through water varying from ankle to chest height prior to ascending towards a network of dry rooms. These rooms pave the way to the grand main hall, a colossal space extending 350 meters in length and 50 meters wide, brimming with relics and remnants of sacrifices.

Following this, an additional ascent leads to the stone chamber housing the Crystal Maiden. This is the skeletal remains of a young female who was offered up in sacrifice and her remains left behind in the cave. Over millennia, her remains have been enveloped by a layer of limestone that glitters like diamonds. The Mayans carried out human sacrifices in a bid to placate the gods and bestow fertility upon the land.