The Antonin nymphaeum
Under Marcus Aurelius (161-180) AD a Nymphaeum or monumental fountain was built against an Augustan terrace wall along the northern edge of the Upper Agora. The water itself was used as an architectural element, falling like a waterfall into the central basin. The fountain was of the tabernacle type in which tabernacles or aediculae are interspersed with hollowed niches in the back wall. Each tabernacle rests on a podium and counts one or two Corinthian columns


For more, see the Sagalassos excavators site on this subject. Please inform me if this link gets broken.