Oagon was a city in the now-lost kingdom of Lirgen. Its location at the mouth of the Black Flow river (in what is now known as the Sodden Lands) ensured it was completely covered by floodwater on the advent of the Eye of Abendego in 4606 AR.1
Just six years prior to its destruction, the advanced nature of Oagon's civilisation may be judged by the launch from the city on Midsummer's Day 4600 AR of the ill-fated spaceship Lirgen's Glory. It rose to the heavens from a launch site in the centre of the city and remained in contact with the Saoc Brethren until the destruction of Lirgen ended all communication with the spaceship.2
The sunken city attracts adventurers seeking the fabled magical vaults of the Hundred Halberd Consortium, a now-vanished merchant company that dealt in magic items and exotic creatures. The city can be explored using giant diving bells of thick glass, which are slowly lowered on cables into the city streets. Accidents are common, and there have also recently been reports of long-tailed aquatic creatures snatching divers.1
For additional resources, see the Meta page.