A few years ago, Nathalie Des Isnards was attending a music festival with her husband David, and planning to watch her favourite group.

Before the show, they headed to the toilets. « I spent 30 minutes in the queue waiting to pee, » she recalls. Much to her frustration, she missed the first part of the concert.

Meanwhile David took just « two minutes », and saw the whole show.

« I was upset. I told myself, ‘We’re in the 21st century, something should be done about that.' »

Read more on BBC News