From: IMDB

Surprising even the most optimistic analysts, LOTR:FOTR sold nearly 2.4 million copies on DVD and VHS in its first week of release in the U.K., wiping out the previous record set by Titanic when it sold 1.8 million copies in its first week of release. At the same time Warner Home Video’s German office reported a first-day sale of one million units in Germany, Austria and Switzerland.