The icon painting of B'hala.
B'hala is the Holy City of Bajor, lost to history 20,000 years ago. The only concrete evidence that the city ever existed was an icon painting, created at that time.
This precious cultural artifact was stolen by the Cardassians during the Occupation.
In 2373, the Detapa Council acquiesced to Bajoran pressure and returned the painting, where it was placed on display in the State Museum in Ilvia.
For 10,000 years, Bajoran archaeologists searched for B'hala without success. According to Zocal's Third Prophecy, only someone "touched by the Prophets" can find the lost city. When the icon painting passed through Deep Space 9 on its way to Bajor, Benjamin Sisko created a holographic re-creation of the city's bantaca spire from the icon painting. Using the spire's reflection in a waterfall, he extrapolated the symbols on the other two sides and determined the coordinates of the lost city. With this data and some revelations from a pagh'tem'far, Sisko found the city buried some 200 meters underground. His discovery of the sacred city served to confirm his status as Emissary, even amongst long-standing critics such as Kai Winn Adami. (DS9: "Rapture")
Excavations of the city began immediately by an order of ranjens. It was found that B'hala was built on the ruins of an even more ancient city, abandoned some 25,000 years ago. In these ruins, directly beneath the Temple of B'hala, Bajoran excavators in 2374 discovered a stone tablet dating over 30,000 years old. The tablet described the Reckoning, a duel between a Prophet and a Pah-wraith contained inside. The battle began when Sisko was shown the tablet and experienced a vision. (DS9: "The Reckoning")