A quick look at: Acueducto de los Milagros, Mérida, Spain.
This Roman aqueduct was dubbed Acueducto de los Milagros ("Miraculous Aqueduct") by the inhabitants of Mérida for the fact that it was still standing, and for the ewe that it evoked.
This aqueduct was located in the Roman colony of Emerita Augusta (present day Mérida), which was founded by Augustus Caesar in 25 BC. The construction of the aqueduct itself is thought to have taken place during the 1st century AD, with later construction or renovations occurring around 300 AD.
The structure was built to supply water to Emerita Augusta. This water was originally brought to the city from Lago de Proserpina -a reservoir which was fed by the Las Pardillas stream, about 5km north-west of Mérida. 38 pillars which stand 25 metres high along some 830 metres remains today. The structure is constructed from opus mixtum.
The Romans constructed aqueducts to supply water from distant sources to their towns and cities, supplying public baths, private households, etc. Water was moved by the aqueducts through gravity, the aqueducts were built on an ever-so-slight downward gradient. This diagram is useful in showing how Roman aqueducts worked.
Photo courtesy & taken by Jane Drumsara.