Encuéntrenos Programa Boston HAPPENSEncuéntrenos 333 Longwood Avenue, 5th floor The Boston HAPPENS Program is located on the fifth floor of 333 Longwood Avenue, across the street from the main hospital. Exit the Patient and Family Garage onto Longwood Avenue and take a right. 333 Longwood is the second building on your right. Copyright © 2008 Children's Hospital Boston