n a first, San Francisco International Airport (SFO) has unveiled a prototype smartphone app that will help people who are blind or otherwise visually impaired navigate through the passenger terminals of the country’s 7th largest airport without a chaperone.

The app was a joint development between SF mayor Ed Lee’s so-called “Entrepreneur-in-Residence Program” and a company specializing in indoor navigation technology called Indoor. It took 16 weeks to develop.