and more history -- as dalilah muhummad takes the 400 meter hurdle gold. it's the first time an american woman has ever done that. it's a perfect 100 for team u-s-a -- nearly doubling the runner up on the medal count. the u-s has 35 gold, 33 silver, and 32 bronze medals -- 100 in total. china is next with great britain with 56... russia has 44... and japan behind with 36. you know the flowering plant alfalfa? used as an herbal drug.. and one neighborhood used to be known for it's alfalfa fields back in the 1800's. 9neighborhoods today visits berkely, that's coming up. but first-- a family desperately searching for their missing son. just how much the flooding is unrelenting -- rising waters in louisiana now moving south. at least 13 dead thousands of homes threatened. and here in colorado scientists have a new way to predict such devastation... seven months later and still no new leads. a family-- now offering hundreds of thousands of dollars to find their missing son... and to rio -- the olympics winding down but the olympic spirit hasn't left the city. w