big cities continue to remain big business, says runner's world molly o'keefe. >> people make them a destination race. >> during the 34th new york city marathon, the race's 1 millionth runner will cross the finish line. it draws runners to the site of the air b and b. >> what we think will happen with air b & b, is it provides a better option for people, and we hope to see more friends and family. >> half a million dollars is the winning purse. but the real money is with sponsors like power bar, who see his appeal to the running faithful. >> we don't just sign up because they tell us to sign up or -- it's more that they believe what i do and i believe what they make. >> these days, big races can also come with big threats. with runners in the country, it's a boost for some but not the city's mayor. >> i've said over and over, there is no alarm for this city. >> a city that's drready to run. i'm mary thompson, nightly business report. >>> for some it's looking like an early black friday. amazon is moving up the free shipping cost for the entire month, offering two new shopping deals e

for more on the growth of the running industry, molly o'keefe joins me here in studio.o bottom line. thanks for your time. why so many women? look back even 15 years ago, a lot of charity drove women into the sport. nowadays, social media to women wanting to encourage friends, family getting involved. we see that social media is really driving a lot of they -- >> would this growth have happened without social media? >> i think so. you are able to track it more. running is such a community sports anyway. women turn to it a little bit more. they are really into the half marathons right now. they're finishing really strong with marathons and outnumbering men in a lot of areas. ofhow is the retail side running changed? >> a lot of the larger big-box out areas forving women so they can have a special experience. a lot of us are moms and shopping for our children. what are you doing when you are in store? you should have a great experience. >> what about the tech angle? well.s a medical angle as you have the wearable monitoring devices. they lead to more awareness of your hea