Fox News’ Jenna Lee got a special look at the halls that held sick immigrants on Ellis Island back in the 1900s.

Ellis Island Immigrant Hospital was known as the largest public health hospital at the peak of its operation. The hospital detained and treated sick immigrants before releasing them to live in the U.S.

Of the 12 million people who filed through Ellis Island, one in five people were detained after their medical inspection. Still, less than 1 percent of immigrants were actually admitted to the hospital.

Officials checked immigrants for a number of ailments, like measles, diphtheria, whooping cough and scarlet fever.

Sick immigrants were detained to determine whether they could be treated and cured. Then, hospital officials had to find someone to pay for the treatment.

Until an immigrant could determine who could pay for their health care, the Department of Labor sent the bill to whichever steamship company delivered that immigrant.

The hospital became the birthplace of 350 babies, though they didn’t get automatic citizenship. About 3,500 people died on Ellis Island.

Some detained immigrants had a prime view of the Statue of Liberty as they underwent treatment, anxious to start their new lives in America.

Watch the video above to learn more about the hospital on Ellis Island.

Scroll down to see photos of what the hospital looks like today.