It's a walkthrough Ice Age 3 exhibit featuring all of the characters in their native environments and is located at the far end of Beanoland.
Here's the press release from Chessington:
Quote:
VENTURE INTO THE ICE AGE AT CHESSINGTON WORLD OF ADVENTURES & ZOO
Experience a whole new world at Chessington World of Adventures & Zoo this summer inside the captivating Ice Age 3: Dawn of the Dinosaurs Adventure. The new attraction in association with Walls’ Lemon Age Lolly will be at the park from 20th June – 31st August 2009 to celebrate the release of the movie Ice Age 3: Dawn of the Dinosaurs on 1st July.
Join your favourite sub zero heroes, Sid, Scrat, Manny and Diego as they journey deep into the Ice Cave. Amidst the snow and ice you will be challenged to stretch your neck like Sid or make yourself look as big as Manny.
You’ll then be transported into the middle of the Jungle, but keep your balance as you try and make it across Lava Falls in Bucks Adventure Trail. Run amuck through the Chasm of Death and hop over the Hump Back Wooden Bridge. As you land back on safe ground you will be rewarded with a sneak preview of the new film.
Guests who visit the Ice Age 3: Dawn of the Dinosaurs Adventures will also have the chance to enter a fantastic prize draw, there are 10 main prizes of a Nintendo Wii with Ice Age 3 game and 20 runners up with each receive an Ice Age 3 game.
Image of the outside of the exhibit:

Image thanks to Colin from
heyuguys.co.uk 