For those 10 years, between 1119 and 1128, the Knights Templar had their headquarters on the Temple Mount in Jerusalem, in what is now the Al Aqsa Mosque. They carried out extensive excavations underneath the Temple Mount. Evidence found today in excavated tunnels under the Temple Mount proves they did this.

And they must've known what they were looking for when they set out from France, those original 9 Knights Templar.

How do you think they knew what to look for and where to look?

Bernard of Clairvaux was the Templars' benefactor and can be credited with the origination of the Order of the Poor Knights of Christ of the Temple of Solomon (Knights Templar). Bernard was a French abbot and founded the Cistercian order.