One of the most popular things for tourists to do in New York City is visiting the Statue of Liberty.
Statue of Liberty National Monument is a national monument comprising Liberty Island and Ellis Island in New York Harbor. It includes the Statue of Liberty, situated on Liberty Island (40°41′24″N 74°02′44″W / 40.689978°N 74.045448°W / 40.689978; -74.045448), and the former immigration depot on Ellis Island (40°41′57″N 74°02′23″W / 40.699300°N 74.039655°W / 40.699300; -74.039655). The Statue of Liberty was dedicated in 1886. The immigration station at Ellis Island opened in 1892 and closed in 1954. – Wikipedia
The Statue of Liberty Monument and Ellis Island are both accessible by ferry from Liberty State Park in Jersey City, New Jersey and Battery Park in Lower Manhattan, New York. Plan a full day for this visit considering you have both Ellis Island, the immigration depot, and long lines for security at the Monument. The park has opened up service to the top of the crown, but tickets are sold ahead of time in limited quantities for each day.