All eyes will be on the Summer Olympics in Rio this August. In addition to checking out the amazing performances, games and matches, you may notice a few grin-worthy moments. Here are a few of our favorites from past games:

• A Bite of Gold

Olympians biting their gold is a podium tradition. Though chocolate coins would be a worthy way to taste victory, what’s the appeal of a mouthful of metal? No one knows for sure, but historical counterfeiting may play a role in the metal mystery. Coins used to contain precious metals that were softer, so money handlers would bite them to test their authenticity. Another explanation may be photogs’ obsession with the pose. The snapshot has become a Summer Olympics staple, and iconic shots are easier to sell.

• Synchronized Smiling

Synchronized swimming is one of the more offbeat Olympic events. But this strenuous sport requires stamina, strength and lots of smiling. If you think it’s hard to smile when you’re having a bad day, imagine holding your breath, exerting an enormous amount of energy—all while smiling! And those smiles pay off positively in the judges’ scores.

This 2008 Olympian said it best: “Imagine doing a four-minute bike sprint while holding your breath in 15-second intervals. And we have to do it all with a smile.”

• Olympians Save their Smiles

Since 2004, a team of dental professionals volunteer to give athletes gratis care. Surprisingly, traumatic care isn’t the most requested service. At the London Olympics, nearly half of participants hadn’t had a dental exam in the last year. The clinic provides cleanings, mouthguards, and on-site dentists during competition. The hope is that athletes return home as more than Olympians—but as oral health advocates.

What’s your favorite Olympic [smile]stone? Share yours below!