Silo 16
Silo 16 was the area on Malcassairo from which the last of the humans took a rocket on their journey to Utopia. The name suggests that there may have been or are more silos across the planet. Prior to the launch, it had served for what seems to have been a long time as a waiting area and "sanctuary" of sorts for humanity. The Futurekind, who hunted and apparently ate humans, were not allowed inside Silo 16. One method of verifying that entry was only given to humans was to examine the entrants' teeth, allowing the guards to look for the distinctive fangs of the Futurekind. Despite this, at least one Futurekind did gain access to the Silo, delaying the ability of the humans to launch their rocket and escape from the planet. (DW: Utopia)
When Malcassairo went nova, Silo 16 and the others were presumably swallowed in the planetary explosion that followed the Utopia Project Rocket's departure. (DW: Last of the Time Lords)