. >> tonight at olympic stadium, david rudisha defended his gold.

. >> tonight at olympic stadium, david rudisha defended his gold.

. >> tonight at olympic stadium, david rudisha defended his gold.

. >> tonight at olympic stadium, david rudisha defended his gold.

. >> tonight at olympic stadium, david rudisha defended his gold.

kenya's david rudisha retained title outsprinting in the final lap, but finished two seconds closer in london 2012 where he set the world record. clayton murphy surged in the last 100 meters of the race to take bronze. u.s. gymnast simone biles fell short to win a gold after falling from the beam. first gymnastics metal for the netherlands. meanwhile laurie hernandez took silver and biles grabbed bronze, her fourth metal in rio. let's look at the metal tally. u.s. is top of the leaderboard. yesterday was the first day of the olympic competition since 2008 that american athletes to failed to win gold in a single event. wow. that's pretty incredible. we have to take a quick break once again. check out world markets live, our blog that runs throughout the trading day. we'll be back in two. narrator: adventure can be found anywhere but the best place to start is in the forest. kubo: i spy something beginning with..."s" beetle: snow. kubo: no. beetle: snow covered trees. monkey: nothing to do with snow. narrator: head outside to discover incredible animals and beautiful plants that come tog