Orolunga was a ziggurat in Chult. It was surrounded by a ruined city of the same name. The ziggurat was encased in a protective magic shell that prevented anyone from ascending it by any means other than climbing the stairs.
Orolunga was a 60-feet-tall brick-and-stone ziggurat with four levels. On the fourth level was an enclosed shrine adorned with labyrinth symbols. The ruins of the city that once surrounded the ziggurat were completely covered by vegetation by the late fifteenth century DR.
The magic that protected Orolunga prevented anyone ascending the ziggurat from doing so by any means other than climbing the stairs. Those who attempted to fly up would rise above the trees but never got any closer to the ziggurat, as if they were flying into a powerful headwind. Those who tried to climb a wall would get halfway up, then inexplicably lose their grip and slide back down. A ladder built to scale a wall never reached the top, no matter how long the ladder. A rope-and-hook thrown up to catch the edge always fell short. Casting teleport or misty step would move the caster sideways instead of up to the next level.