beyond the Barrier.

At first glance, it differed little from any of the desert country where
he had lived all his life. The ground shelved gradually away from the
rocky rim on which they stood; far off, against the darkening eastern
sky, blue mountains rose murkily, but between here and the ranges lay a
vast shallow depression, an arid sink floored with wind-rippled sand.
Perhaps it had been a lake-bed once, before natural or unnatural
cataclysms, and the millennial drying-up of all this country, had
emptied it of water. Or perhaps--as its circular form suggested--it was
one of those other, mysterious depressions which were scattered
irregularly across the face of the earth where no lakes had ever been;
those, legend said, were scars left by the ancients' wars.

The rich light of the declining sun fell at a shallow angle into the
miles-wide bowl and brought out with startling clarity the maze of
wheel-tracks, crossing and criss-crossing, which covered its sandy
expanse and testified to a fever of recent machine activity there. The
light gleamed, too, here and there, upon scurrying metallic shapes, that
raced by ones and twos or in trickling columns to and from the center of
the bowl, where--

Dworn strained his eyes and his capacity for belief in an effort to make
sense of the structures there, miles away. He was not very successful,
for the scene was too unlike anything he had ever looked on before.

There were certain races which built stationary dwellings--Dworn knew of
the scale-makers who lived, in colonies sometimes of considerable size,
beneath individual armored, anchored domes sunk into the face of some
impregnable rock; he knew of the sand devils with their pits, and now he
had seen also how the spider people nested. But the huge buildings that
loomed yonder, lowering and windowless, and the winged things clustering
thick on the ground about them, were such as he had never seen in his
nomadic life.

Atop a slender tower that spired above the squat structures he could
make out something which turned and turned, something like a broad net
of lacy wires, revolving steadily from east to west, from north to
south. Strange, too, the smooth-surfaced ways that radiated outward in
four directions, like an immense cross, broad paved roads that came to
abrupt dead ends a mile or more from the central buildings.... After a
moment, though, he guessed that those were runways for the aircraft
which flew from this place