Next to the offering room is the barque sanctuary. The boats that were used to carry the images of the gods from Karnak were kept here while the gods visited Luxor. In Luxor, this room runs along the axis of the temple and was transformed into a chapel by Alexander the Great, who appears before Amun in several of the wall decorations on both the inner and outer walls. Other rooms open off the sanctuary, as well. The "Birth Room" is one of the more popular with its relief decorations showing Amenhotep's divine conception and birth. Opet means "secret chamber" and refers to the private chambers in the temple where the king's ka was born. This chamber was built on the remains of what was believed to be the primordial mound that first rose from the waters at the creation of the world. The Festival of Opet was celebrated as the birthday of the King's Ka.