He had already demanded the reason for the signal from the Mare Imbrium.
We had been following him toward the Mare Imbrium; we were at its borders now.
We came to the ledge with the plains of the Mare Imbrium stretching out beneath us.
An hour had passed since we turned from the borders of the Mare Imbrium.
The great smooth surface to the west of Archimedes is the Mare Imbrium.
We were on the curving side of the Archimedes wall which fronted the Mare Imbrium to the north.
We came to a ledge, with the plains of the Mare Imbrium stretching out beneath us.
I saw many glances cast out the dome side windows toward the distant plains of the Mare Imbrium.
Sweeping around from the Mare Imbrium, the plains were less smooth.
The Mare Imbrium, covering 340,000 square miles, is sparingly dotted over with craters.