Krakatoa

Krakatoa is a volcanic island in the south Pacific Ocean. It erupted in 1883.

Sometime prior to his third incarnation, the Doctor witnessed the eruption; during this event, he also hears Primords for the first time. (DW: Inferno)

That same day, a sketch of Ninth Doctor washed up on a beach on Sumatra. It eventually found its way into Clive Finch's collection of artifacts related to the Doctor. (DW: Rose)

Tenth Doctor and Rose Tyler visited Indonesia, encountered the alien Chalderans and were hung upside down forcing the blood to go to their heads. The Doctor used his sonic screwdriver to free them, Rose having a nasty landing when she hit the ground. They managed to escape in the TARDIS just as the volcano erupted. (DWAM: Under the Volcano)

The Krakatoa eruption also caused one Xylok to be freed. This Xylok became Mr Smith many years later. (SJA: The Lost Boy)