Among the most important structures in the oasis is the late-19th century fortified residence of Sheikh Ahmad bin Hilal Al Dhaheri, the Representative of the late Sheikh Zayed bin Khalifa Al Nahyan, Zayed the First (r. 1855-1909) in Al Ain. The house provides a fine example of a residential fort built to protect the oasis, the falaj and farms and houses that fell under his jurisdiction. A nearby mosque reflects the simple design and construction that characterised the architecture of Al Ain at the time. Located to the south of Jimi Oasis is the round Jimi Watchtower, built by Sheikh Ahmad bin Hilal Al Dhaheri in the second half of the 19th century. The 14-metre tall tower protected the shariaa of the falaj, the point where the underground water supply comes to the surface and is accessible for public drinking and irrigation.