The Meta Sudans was a large monumental conical fountain in ancient Rome.
The Meta Sudans was built some time between 89 and 96 under the Flavian emperors, a few years after the completion of the nearby Colosseum. It was built between the Colosseum and the Temple of Venus and Roma, close to the later Arch of Constantine, at the juncture of four regions of ancient Rome: regions I, III, IV, X.
A meta was a tall conical object in a Roman circus that stood at either end of the central spina, around which racing chariots would turn. The Meta Sudans had the same shape, and also functioned as a similar kind of turning point, in that it marked the spot where a Roman triumphal procession would turn left from the via Triumphalis along the east side of the Palatine onto the via Sacra and into the Forum Romanum itself.
The Meta Sudans was built of a brick and concrete core, faced with marble. It seems to have "sweated" the water, rather than jetting it out the top. This may mean that it oozed out the top, or perhaps that water came from holes in its side. The monument is estimated to have stood up to 17m high; until the 20th century, its concrete core was still over 9m high.