It changes week to week but right now 'Captain America: Winter Soldier' is the #1 movie in the world. It made $96 Million this past weekend in the U.S. and another $207+ Million from other countries for a total of ($303+ million).
Noah was #1 in the world last week when it opened at $43.7 Million in the U.S. As of now the worldwide gross for Noah is ($178.+ million)
The #1 movie of all time is 'Avatar' with over $2.7 Billion worldwide. The #1 Animated movie is 'Frozen' with $1.1 Billion worldwide.
I suspect 'Captain America' will remain number one in the world until the sequel to Spiderman comes out next month
www.boxofficemojo.com provides domestic and worldwide totals for movies. However no one in Hollywood talks about adjusting for inflation. To my knowledge 'Gone With The Wind' had sold more (tickets) than any other movie.