Ubar, a legendary ancient kingdom, was said to have been situated in Rub Al Khali desert, also referred to as the Empty Quarter in Oman. Its history spans 1000 years. Ubar was the earliest known central shipping trade zone for frankincense. According to the legends, there once lived a Sheik who had built a gigantic fortress with towers, which was surrounded by tents. The myth goes on to say that, this dessert "swallowed" Ubar, causing it to vanish without a trace. There are beliefs that this could have been either due to a natural disaster or as a punishment by God. After the disappearance of this city, that area later gained popularity as the "Atlantis of the Sands".