Heidi Klum stretched her supermodel curves on the beach in Porto Cervo, Italy, on Sunday. At one point Heidi stripped down and went topless to perfect her tan. She was joined by her husband Seal and their four kids, Leni, Lou, Johan, and Henry, as they basked in the Sardinian sunshine. Heidi and Seal shared a few sweet kisses, and PDA is certainly welcome for the Klum-Samuel crew. The kids all played together and had their own cute moments, with Leni posing alongside her little sister while Henry and Johan hit the water on a raft with their dad. Seal once again played photographer for the whole picturesque outing, though Heidi took a turn behind the lens as well. Heidi Klum's bikini-filled vacation with the family kicked off almost two weeks ago when she brought the kids to join up with Seal on tour in Europe. The results of Heidi's Summer workout initiative are clearly paying off, though it's also Seal's six-pack's chance to shine in our 2011 PopSugar Shirtless Bracket.