The Meidum pyramid, often referred to as the "collapsed pyramid," is located near the Fayoum oasis and is generally attributed to the reign of Sneferu of the Fourth Dynasty, although some theories suggest an earlier construction under Huni. It originally began as a seven or eight step structure before evolving into a smooth sided pyramid that subsequently suffered a partial collapse, exposing its inner core and revealing key information about early pyramid engineering experiments. Most modern interpretations attribute the failure to structural design limitations and foundation instability, rather than to some ancient catastrophic event, perhaps during the Pharaonic period or earlier.