M.R. Rao, an 84-year-old walking enthusiast, and five-year-old Avni Juneja will be the key highlights of the Mumbai Walkathon, set to take place in suburban Juhu on Sunday, March 16. The event will be flagged off at JVPD Grounds, Juhu, guiding participants past Amitabh Bachchan's residence, towards Juhu Beach, and back.