Open House New York Weekend is the city’s largest free, public architecture and design festival. The event was founded on a simple but powerful idea: The best way to educate the public about architecture and design is through direct access to buildings and the people who help design, build, preserve, and activate New York. Bartow-Pell Mansion Museum is a participating destination and will be open free of charge between 12 and 4 p.m. on Saturday, October 16 and Sunday, October 17.