Maya structures discovered are numbered from 1 and up. This model from the British Museum features the main architectural structure of a Maya temple, Structure 23, in a Maya city called Yaxchilan, constructed by successful Maya rulers between AD 400 and AD 800. Lord Shield Jaguar and his son, Lord Bird Jaguar, reigned this city during the seventh and eight centuries AD. Many Maya structures would be aligned on either the summer or winter solstice sunrise, on which days the rays of the rising sun would shine through the doorways and light up sculptures of rulers inside. Similar sculptures once existed as exterior decoration to these structures, but few have survived till present day.