Of course, the episode also marked Peter Capaldi and Steven Moffat’s last main-series outing, the duo only having the Christmas special left.
Whoever takes the role, they will join Capaldi, along with The First Doctor, in this year’s Christmas special, which will be broadcast Christmas Day on BBC One.
Attention has, as you would expect, turned to one question above all others: ‘Who will replace Capaldi as the Doctor?’
Doctor Who’s most recent series finished with an emotional farewell to various characters, possibly including Pearl Mackie’s Bill.