It was if the city knew about Percy's dream of Gaea. It knew that the earth goddess intended on razing all human civilization, and this city, which had stood for thousands if years, was saying back at her: You wanna dissolve this city, Dirt Face? Give it a shot. In other words, it was the Coach Hedge of mortal cities- only taller.
Rick RiordanNo matter how many times Percy killed them and watched them crumble to powder, they just kept re-forming like large evil dust bunnies.
Rick Riordan