The Grand Sump Chamber of Entry hall 910 was a huge, eight-sided water tank carved out of bituminous shale. It measured three hundred paces across, designed by the First Dynasty to absorb the excess discharge of forty drainage galleries. The black shale walls were polished smooth by hundreds of years of gritty silt-wash, banded with deep level striations where the seasonal waterlines of twelve dynasties had left their hardened tidemarks. Around the outer edge ran a vaulted gallery supported by squat, thick-waisted pillars of dark red stone, while thirty arm-lengths above the floor hung a fine, detailed network of narrow iron narrow high walkways suspended from the ceiling by heavy forged eyebolts anchored into the living rock with molten lead.
The water below was no longer ordinary black salt water. It was an ontological slurry, dense and thick, sticky. It glowed with a greasy, violet-black iridescence where the dissolved embers of put out sky realms swirled in sluggish gyres. The liquid gave off a heavy, choking vapor that tasted of burned zinc, cold animal fat, and crushed river-snails. Every ten seconds, a massive pulse of tightly packed air burst from the underwater under-road drains. It sent geysers of foaming, dark froth twenty arm-lengths into the air, drenching the iron narrow high walkways in bitter spray that crusted right away into a powdery, lilac-tinted salt.
