The Salt Lions
From The Fifth City Wiki
"Two basalt beasts, cathedral-sized. They frown eternally at each other across the black waves. The north one carries an encampment: creeping human figures eat away at its features like rot, pick-pick-picking. There's a supply dock below."

Two giant basalt lions that face each other across the Zee. Are they sphinxes from the Second City? It's very plausible; the stone they're made of is called sphinxstone...
The Bazaar commissions large amounts of sphinxstone to be quarried from them - they're building something, somewhere beneath London. Irem is built of sphinxstone, which, while in transport, may start crying. This all may have something to do with lacre (the Bazaar's tears) or the mysterious Stone Pigs.