Singing Towers

The Singing Towers of Darillium was where the Eleventh Doctor spent what he knew would be River Song's last night with him. River would ascertain this unfortunate truth after noticing the Doctor had gone to unusual lengths to prepare for their date, sporting a tuxedo and a new haircut. When the date reached an emotional low for him, the sorrowful Doctor could not hold back the pain he felt over the fate River would be subjected to, and began to cry. (TV: Forest of the Dead)

The Doctor also met a past version of himself on this night, when River went into the wrong version of the TARDIS. The younger Doctor asked his future self if this was to be the last time he would see River; the future Doctor replied, "Spoilers." (TV: Last Night)