Roman aqueduct
Rome's first aqueduct was built in 312 BC, and supplied a water fountain at the city's cattle market. By the 3rd century AD, the city had eleven aqueducts, sustaining a population of over a million in a water-extravagant economy; most of the water supplied the city's many public baths. Cities and towns throughout the Roman Empire emulated this model, and funded aqueducts as objects of public interest and civic pride, "an expensive yet necessary luxury to which all could, and did, aspire".
Seneca Aqueduct
Seneca Aqueduct — or Aqueduct No. 1 — is a naviduct that carries the Chesapeake and Ohio Canal (C&O) over Seneca Creek in Montgomery County, Maryland. The C&O built eleven aqueducts along its length. Seneca Aqueduct is a unique structure, not only being the first built, but also the only red sandstone aqueduct on the C&O−and the only aqueduct that is also a lock (Lock 24, or Riley's Lock). It is located at the end of Riley's Lock Road in Seneca, Maryland.