Wintergrasp

From wow.incgamers.com

Wintergrasp is a zone in Northrend, the new continent introduced in Wrath of the Lich King. Blizzard has stated that this area will be an outdoor PvP-only zone, and will contain

• Siege Weapons,
• Destructible buildings,
• Multiple objectives with lasting effects.

In this zone, players are auto-flagged for PvP the moment they enter, even if they're on a PvE (Normal/RP) server. This is a first for WoW, no other zone is like this in the entire game.

There will be multiple objectives and a meaningful, persistent effect as either side wins the PvP battles. Blizzard intend to include as many of the well known siege weapons from earlier Warcraft games as possible, such as Steam Tanks and Meat Wagons. Siege weapons are intended not as a player owned item, but to be tied in to specific objectives or events. They will also be a slow way to travel, so there should be plenty of action around the siege engines as they move about the area.

The zone itself is said to be a huge frozen-over lake, about the size of Westfall. It is centrally located in Northrend, so as to be fairly accessible from the whole continent.