Beverly Hills Heidi Klum

No more topless tanning for her!

Heidi Klum headed to Tulum, Mexico with her much younger boy toy Vito Schnabel last week, and the 40-year-old model was photographed without a bikini top on the beach. We've seen her boobs before and she's pranced around in countless skimpy swimsuits, but we were pretty amazed that she had the balls to do that at her age -- and after four kids!

Heidi posted some vacation snapshots on Instagram and wrote, "Ocean.... sand... sun..... happiness," and though we initially thought this romance was just a fling, it looks like things are getting pretty serious!