On the southern outskirts of Mehrauli is this large tank
(Hauz) said to have been built around 1230 by Shamsu'd-Din Iltutmish.
Legend Of Hauz-I-Shamsi
The tradition is that the Prophet appeared once to Iltutmish in a dream
and pointed out this site to him as suitable for building the tank, which
he had in mind. The next morning Iltutmish noticed here the print of one
of the hoofs of the Prophet's horse, around which he built a domed
platform and excavated the tank.
The famous Moorish traveller Ibn-Batua was struck by the vastness of this
tank, which was supplied by rain water and in the centre of which stood a
double storeyed stone pavilion, reached only by boats when full.
A red sandstone domed pavilion resting on twelve pillars located near the
south-western corner of the tank, but originally believed to have been
situated in its centre, is identified with the pavilion built by
Iltutmish. The original stone with hoof print is believed to have been
removed, the present stone being a later renewal.
The waters of the tank are regarded as sacred, and several graves of
Muslim saints lie around it. The procession for the fair called
'Phulwalon-ki-Sair' or 'Sair-i-Gulfaroshan', when flower-vendors present
flower-bedecked large fans at the dargah of Qutub-Sahib and at the
Jogamaya temple, starts from the overflow outlet of this tank, called "Jharna".