captioning sponsored by newshour productions, llc >> yang: good evening, i'm john yang. judy woodruff is ay. on the newshour tonight, wallet stre takes another plunge: a volatile day leaves the stock market down more than 1100 points, the largest one-day point drop ever. then, republicans are split on what the nunes memo means fores the russia igation, while we take a look at how russia's cyber tactics played into calls for its release. plus, five months afte hurricane harvey slammed into houston, city officials face the task of rebuilding the city to withstand the next s >> we need to turn this area into much more green space. sometimes you have to look at mother nature and say mother nature wins. >> yang: all that and more on tonight's pbs newshour