The Great Towny Glitch of 2015 was an event that happened on May 29th, 2015, at about 3:00 P.M. All towns and nations were deleted, and with it the economy failed and lots of money was lost. Players scrambled to reclaim cities and gain power. Cities such as Mandalay were looted and fear rose from the Earth.
Even though the Glitch was primarily seen as a loss, it helped at few. Some players who had already planned moving, such as FuegoTheViking, to leave their old towns and found new ones.
Here is a list of cities that survived the Glitch and was carried on after it:
Madrid (for the second time the city had to be reclaimed, after a previous towny glitch that affected only Madrid.)
Atyrau (though under new government)
Machu_Picchu (it would collapse later, when an international coallition attacked Machu and `Incan gods told the mayor to move to Antarctica`)
Butter's Village (collapsed not long after)
...and some others