and today, the white house said summitt will be honored with the presidential medal of freedom. the nation's highest civilian

honor for her inspiring work as a coach and an advocate for a cure for alzheimer's. our report tonight from nbc's you have to find the time that you think is the right time and that is now. >> with humor and grace, the winningest coach in college basketball, women's or men's, stepped aside after 38 spectacular years. >> it was really a great ride for me. it has been a privilege to make an impact on the lives of 161 women who have worn the orange. >> she grew up on a dairy farm and turned hard work, a ferocious competitiveness, and that trademark stare into eight national championships and 1,098 career victories. >> the way she coached the team, the way she conducted herself, you know, the way she did

things, i think it transcends that gender. >> someone larger than just women's basketball or sport. she's known for integrity, compassion, doing the right thing. every player with her for four years graduated with a college degree. ashley robinson is now playing professional basketball. >> the motherly side, the lady that gives you advice on men, on the pros, on just life in general, that's pat summitt to me. >> last august, at age 59, summitt revealed her latest opponent. >> the doctors at the mayo clinic diagnosed me with an early onset dementia. alzheimer's type. >> some urged her to retire and disappear from public view to preserve her image as the disease progresses, but she was on the bench all season coaching and vows to stay active as coach emeritus and with her foundation to fight alzheimer's. >> i made a choice early in my career to challenge myself, to

step up my game each and every day. >> what makes her distinctive is her lack of fear. most people are afraid of alzheimer's disease, afraid of what people might say about them because of it. pat's not afraid of any of those things. >> even today, her focus was on others. >> you know what, it was a good day. it was a good day. i assured the players that i would be here, and i'd go with them and, you know, stay with them. >> she gave her whistle to tennessee's new coach. and later went to practice. once again, leading by example. >> hopefully we can, you know, have a good fight. and that's exactly what i want to do. >> lisa myers, nbc news, washington. and we're back in a moment with the loss today of an american music legend. ♪ take a load off annie

♪ the night they drove old dixie down ♪ levon helm has died. he played in a band called "the band." mostly drums, but a bit of everything, and he made "rolling stone's" top 100 vocalists of all time. with songs like "the wait," "up on cripple creek," and "the night they drove old dixie down." the proud son of turkey scratch, arkansas. he was good at a lot of things including acting. he played ridley, the sidekick and narrator in the "right stuff" who always seemed to have a stick of beamen's chewing gum for his friend, chuck. and he also did a stint at loretta lynn's father in "coal miner's daughter." he was famous for his midnight ramble sessions. he bravely battled throat cancer and toured to the very end. levon helm was 71 years old. stanley resor died. he was secretary of the army for six years at the height of the vietnam war.

appointed by president lyndon johnson. after graduating from yale, he joined the army. in world war ii, he saw heavy combat in the battle of the bulge, earning him a purple heart and bronze and silver stars. in later years, he was an arms reduction negotiator and u.s. ambassador. stan resor was 94. and quite a visual moment yesterday in dearborn, michigan, at the henry ford museum. president obama sat in the same city bus from montgomery, alabama, where rosa parks refused to give up her seat. the president was there for a fund-raiser. after that moment, he spoke of parks' courage and tenacity. when we come back, how saving some of the most beautiful sights on earth may hold the key to saving a lot of human lives.

next at 6:00, a vip night and an historic night for the 49ers. a live look now from our nbc chopper at the groundbreaking ceremony for their billion-dollar stadium in santa clara. we have a report tonight on our planet as we mark earth week at nbc universal with an example of how connected we are to the environment. effective cancer treatments are being discovered. more than that, their building blocks come from the ocean, which is just one more reason to protect it. our chief environmental affairs correspondent anne thompson has our report tonight from key west, florida.

>> the kaleidoscope of life in the coral reef under the turquoise waters under the florida keys is a magnet for tourists. does all of this actually help you preserve the reef? >> i think ultimately it does. people become advocates for the reefs they had experiences with. >> with corals already under siege from pollution and climate janj, stephanie weir things the best way to connect people to the reef may be through what snorkelers can't see. the chemistry that helps coral survive may help people, too. >> what we're doing is taking advantage of the chemistry and turning the chemicals into drugs to save lives. >> scientists thing the reefs could yield new therapies for alzheimer's disease, parkinson's and lupus. all because of the success they've already had developing drugs for cancer. this woman beat leukemia with help from a chemotherapy drug originally derived from a sea sponge. without it, she said she could have died at age 26.

did you ever imagine what could make you better would come from the sea? >> not at all. i spent most of my life swimming in the ocean, but i didn't assume it would have anything to do with my cancer. >> without the reef and doing that conservation, we have no starting point. >> dr. edwards developed new drugs at esan, a lab that developments halavan, a drug that was recently approved for late-stage breast cancer. a japanese scientist discovered it in a pacific ocean sea sponge. >> in order to make this drug by synthesis, we would require over 60 steps. the typical drug is about ten steps or less. >> scientists need just a small sample from the reef to unlock the mysteries, but they do need the reefs. >> it's like the new york city of the ocean, where everything is happening, hustle, bustle, neon lights. >> a small contribution that could make the big difference for the oceans and mankind. anne thompson, nbc news, key west. >> that's our broadcast on a thursday night. thank you for being here with

us. i'm brian williams, and of course, we hope to see you right back here tomorrow evening. good night. >> announcer: nbc bay area news starts now. >> right now at 6:00, years in the making, and now the moment is here. a live look at the future site of the 49ers and their billion-dollar stadium in santa clara. the vips are arriving and taking their seats and those golden shovels are ready for the groundbreaking ceremony. >> let's show you what it looks like from overhead from our nbc chopper. a big party, a big night for the bay area's oldest sports franchise. good evening. i'm jessica aguirre. >> and i'm raj mathai. political