Gisele Bundchen watches her adorable 20-month-old son Benjamin at the playground on Thursday (September 1) in Boston, Mass.

The 31-year-old Brazilian supermodel was joined by husband Tom Brady’s father, Tom Brady Sr., who snapped pics of Benjamin with his cell phone.

Gisele recently teamed up with the United Nations Environment Programme to draw attention to the vital role forests play in our lives.

She shot a video in the Amazon, which will be released on her YouTube channel Monday, Sept. 5 – World Amazon Day.

For a chance to win a copy of Vogue Brazil’s July 2011 issue autographed by Gisele, check out her Twitter account and Facebook page on Sept. 5 for more info!