Working Lives Mexico: Car keeper
Petra Lopez earns money in one of Mexico City's more enterprising ways.
Known as a franelera, Mrs Lopez will watch your car for two minutes or two hours for a tip.
As well as the passing customers, she also has a handful of regular clients who have come to know and trust Petra with their expensive vehicles. She takes their keys and will make sure that their cars are carefully parked somewhere on the city's busy streets where they won't be towed away.
It is semi-illegal work, with the city authorities recently clamping down on the practice. But that doesn't deter her.
"I've never once had a car towed nor damaged in any way while it was in my care," she says proudly. She has been doing this job for 16 years now and is part of the huge informal economy in Mexico.
Indeed, her whole family is, as it is a job she shares with her husband and eldest daughter. But her large family - she has five children - can sustain itself well with this kind of ad-hoc street work.
And on Mexico City's chaotic streets there are plenty of people in need of her expertise.