Mount Moriah and the Mount of Olives were separated by the Kidron Valley, and to allow the Kohanim to easily reach one from the other a walkway was constructed starting from the eastern gate of the Temple Mount. This walkway was supported by two levels of arches, with the columns of the upper level located over the airspaces of the lower level (Parah 3:6). This arrangement ensured that anyone standing on the walkway would be completely protected against the tumah of a grave that might be present in the ground below (see this post for more details).
|The 71 members of the Great Sanhedrin line the walkway to greet the Kohen bringing the red cow to the Mount of Olives (see Parah 3:7 with Tiferes Yisrael §53).
One of the key requirements in the preparation of the red cow is that the Kohen carrying out the procedure not only be located east of the Temple but he also must be able to see the opening of the Sanctuary as he sprinkles the blood of the slaughtered cow. The elevations of the Temple were such that, in order to see the opening from his vantage point in the east, he must look over the wall of the Temple Mount, through the gate leading into the Women's Courtyard, through the Nikanor Gate, and then into the Sanctuary.
|Sight line from the Mount of Olives to the entrance of the Sanctuary.
|The large structure where the red cow was prepared. The archway in the front leads to the mikveh.
The Mishnah (Parah 3:10, 4:2) refers to this structure where the cow was prepared as a גת, winepress, since at its top was a depression in which the cow would be burned. Within this depression they built a large pyre, wide on the bottom and narrower on top, like a tower (Parah 3:8 with Rav). The cow would be slaughtered atop the pyre, its blood sprinkled toward the Sanctuary, and then the pyre would be ignited. After the fire had burned out, all of the ashes would be collected and then used as needed to purify people or utensils which had contracted corpse tumah.
|The Kohen prepares the red cow on the pyre.