This was the spring of Zam Zam, sacrosanct in Islam. Water from Zam Zam is still drunk. Given such extraordinary demand, how is it that Zam Zam remains inexhaustible if it is only a spring? But the team also discovered that Zam Zam was connected to an underground river. At some point long past, a geological tremor had cracked open the earth, creating the spring of Zam Zam from this river.

Source: Pakistan Today July 16, 2019 16:30 UTC