ILM go into more detail on how they recreated New York for The Avengers.
Behind the Magic: The Water of "Battleship"
ILM have overhauled their award winning fluid simulation system for the water in Battleship.
Behind The Scenes With ILM
See the role ZBrush played in ILM's pipeline for The Avengers film.
Avengers: Age of Ultron - Casting the VFX Vendors
fxguide have created a very thorough article about the VFX vendors contributing to the massive Avengers: Age of Ultron.