Pompeii

Pompeii was a city in Italy.

A group of Pyrovile landed in the region and slept for millions of years until awakened by an earthquake in 62 AD. At this point they set in motion a plan to xenoform the earth into a planet of fire, so it could become their new home. In 79 AD, the Tenth Doctor and Donna Noble arrived, and foiled the Pyroviles plan. Unfortunately, while this saved the Earth, it also triggered a catastrophic eruption of the volcano known as Mount Vesuvius. The eruption completely destroyed the city and killed most of its population, 20,000 people. The eruption was so powerful that it briefly created a time rift, which by echoing back in time granted a number of citizens precognitive powers.

The Seventh Doctor and Melanie Bush arrived in Pompeii one day before the eruption and tried to escape from the coming eruption. The Doctor's TARDIS was buried in city. (BFA: The Fires of Vulcan)

This event was, according to the Doctor, a crucial and unchangeable event in history. Jack Harkness in his rogue days also claimed it was an excellent setting for a time agent con job. (DW: The Empty Child / The Doctor Dances) Eventually the city was rediscovered and Humanity remembered its fate. (DW: The Fires of Pompeii)