the final section of that jt project. the legal challenge coming hours after the pipeline s developer said it had started the process of laying pipe under the missouri river. the tribe could claim a leak could contaminate their water supply. the developer insists it will be safe. the news from our world, the world of broadcasting, bob costas announcing today he is stepping down from nbc s prime time coverage of the olympics. that s something he has been leading for 11 olympic games going all the way back to 1992. costas is passing the torch, so to speak, to mike tirico. he ll start with next year s winter olympics in south korea. i am going to be like the rest of the country, watching mike tirico, who will be an able successor, in korea for the winter olympics beginning a year from today. so you re giving up the olympic gig? yeah, i am.