The first historical building that comes to mind when talking about Laleli is the Laleli Mosque. Sultan Mustafa the 3rd made the mosque built between 1760-1763 and the mosque gave its name the area. The name of the mosque, in turn, comes from the fact that Mustafa the 3rd gave the name of Father Laleli, whom he considered his parent, to this mosque. The mosque complex was damaged in a fire in 1783 and was then repaired in a very short time. And another fire in 1911 damaged the madrasah and the road building works damaged many other additional buildings to the mosque. The architect of the mosque was Mehmed Tahir Ağa. However, it is said that the chief architect of the period, Hacı Ahmed Ağa, also contributed to the building of the mosque. The mosque is within Laleli Social Complex. The tombs of Mustafa the 3rd and Selim the 3rd is within the Mustafa the 3rd tomb near the mosque.