the tardis lands the airborne city of Columbia

[zebaroth]

doctor where are we now asks Clara the airborne city of Columbia neither had i until the other day
says the doctor'

the reason

brother and sister Robert & Rosalind Lutece and there invitation the Lutece Device
is unavailing Time and space because Zachary Comstock has use the machine to try
and become a timelord he died broker dewit has become the leader of Columbia after
Robert & Rosalind Lutece the Lutece Device to make this a realty but now the Lutece Device is overloading
and they can't shut it down

can the doctor Shut it down before time and space is damaged beyond repair

[Catsmate]

Interesting idea. Floating cities and palaces were a feature of the Traveller universe, highly suited to attempts to drop them on the populace below.