Daniel traveled to Atlantis to access the Ancient library database, hoping to find the locations of Castiana and Sahal, two worlds where the Sangreal might have been hidden. The holo room on Atlantis uses a holographic interface, however Morgan Le Fay, an ascended Ancient, appeared in place of the hologram. When Daniel asked for the Ancient names of Castiana and Sahal, Morgan replied, "Taoth Vaclarush and Valos Cor," and she provided the gate addresses for the two worlds: 29-3-6-9-12-16 and 29-18-19-20-21-22.
Episode Reference: The Pegasus Project
Stargate Coordinates for Taoth Vaclarush and Valos Cor (Castiana and Sahal): 29-3-6-9-12-16 and 29-18-19-20-21-22