Three levels of tunnels used to carry water to the building.
Sixteen-cubit-deep columns center the pit and when water used
to reach that level, special ceremonies were held for the
was built by an order of Abbasid
Al-Mutawwakel in 861; the aim was to measure the river's flood
to predict the annual harvest.
The basic structure of the monument is the oldest of Islamic
eras in Cairo. However, the supplementary building was restored
several times. The housing of the Nilometer was built only
in the 19th century. It is remarkable for its Turkish-style
The Nilometer is no longer functions because the water tunnels
is now blocked up.
The monument is often closed but the custodian who lives nearby
could be fetched by asking any of the locals.