The Battle of the Pelennor Fields:

One of the major battles in the War of the Ring, it occurred over the days of March 13th to 15th. It was during the days of this battle that the following happened:

Théoden, King of Rohan was slain
Merry and Éowyn slew the Lord of the Nazgûl
The Gates of Gondor were broken by the rams of the host of Mordor under the guidance of the Lord of the Nazgûl.
The first and second circles of Minas Tirith were set to burn by the Enemy.
Denethor, Steward of Gondor attempted to burn both himself and his son, Faramir. Faramir was saved by Gandalf and Beregond, but Denethor killed himself.
Aragorn brought the fleet from Pelargir and turned the tide of battle
The Rohirrim host arrived.

The forces of the West were victorious in this battle, though with losses.