For years, Earth's point of origin was unknown, as the Egyptians had placed two figures praying by the symbol of the pyramid. Daniel Jackson eventually recognized the mistake, and the Tau'ri were able to link to Abydos. (Stargate) As part of a personal preference, when the point of origin hits the seventh chevron, Walter Harriman will announce "chevron seven locked", as a way to change things up. (SG1: "Children of the Gods", "Heroes, Part 1")