What is the main idea of this passage? [br] [originaltext] Three summers ago

Three summers ago, a young boy named Robert from the Harlem area of New York City found a special second home. He traveled away from the city to live with the Lober family in New York State spending the summer playing with other children, swimming and sailing a boat. Today, Robert continues to visit the Lobers who consider him a part of their family.
    This special visit was made possible by an organization called the Fresh Air Fund started in 1877 when New York City was overwhelmed with the disease tuberculosis. Many children lived in crowded apartments. This accelerated the spread of the disease. So getting these children "fresh air" in the country was seen as a solution to this problem.
    Today, the Fresh Air Fund still helps children from low-income communities in New York experience life in the country with a host family. Those children enjoy a free holiday and take part in activities they would not normally experience in the city. More than 65% of the children who visit a host family are invited back the next year. In this way, the children and families often maintain their friendships. Since it began, the Fresh Air Fund has provided free summer holidays to more than one million seven hundred thousand children from low-income communities.  More than ten thousand New York City children enjoy Fresh Air Fund programs every year.