The Vanishing Ziggurat
Every twenty years of so¸ calamities precede the appearance of a ziggurat that remains in place for a few days at most. Tales of treasures¸ demons¸ and knowledge from beyond this world run rampant. Except¸ no one ever left it alive before the ziggurat. Hurry¸ time may be of the essence. This 8-12 hours dungeoncrawl adventure can be placed in Ravenloft or any setting of your choice is best played with a group of 4-6 characters of level 5-10 (optimized for level 7s).