After visiting the Statue of Liberty we went to Ellis Island.
The museum at Ellis Island is very large. We did not have enough time to tour the entire building. There is an interesting movie which describes the immigrants journey and what they encountered once they arrived at Ellis Island.
If you are planning to visit Ellis Island, you should allow several hours to tour the facility. There are no security checkpoints within the museum, so once you get off the ferry you are free to wander everywhere.