In the end, it seems to have been the neighboring abyss which received the greatest colonization. This was partly due, no doubt, to the traditional sacredness of this special region, but may have been more conclusively determined by the opportunities it gave for continuing the use of the great temples on the honeycombed mountains, and for retaining the vast land city as a place of summer residence and base of communication with various mines.
The linkage of old and new abodes was made more effective by means of several gradings and improvements along the connecting routes, including the chiseling of numerous direct tunnels from the ancient metropolis to the black abyss—sharply down-pointing tunnels whose mouths we carefully drew, according to our most thoughtful estimates, on the guide map we were compiling.
It was obvious that at least two of these tunnels lay within a reasonable exploring distance of where we were—both being on the mountainward edge of the city,