My first visit to a favela, one of the most famous urban slums in Latin America, was unexpected. As a result of poverty, huge waves of migrants move to the countries' main cities and end up living in these ramshackle settlements, which lack basic health and sanitation services.

The so-called favelas of Brazil are known as ranchitos in Venezuela, pueblos jóvenes in Peru and villas miseria in Argentina.

At a meeting in New York, I got to know a young Brazilian physician — Dr. Paulo as everybody calls him — and we became friends. He told me repeatedly that if I ever was in Rio de Janeiro I should visit him. He said he would take me to the best places in Rio de Janeiro where he lives and has an active practice that puts him in touch with all segments of Brazilian society.