The trash fence is an orange fence that encircles the whole event; you are not allowed to cross it during the event.
From the man walking alone, go to the trash fence and see the expanse of the Black Rock Desert before you. It is the most breathtaking view. Don't try to walk out there; it is a long way, sometimes, depending on the heat, too long of a ride on a bike.
But the view is worth every minute you spend traveling. It is one of the quietest places in the city, and you always so truly appreciate the natural beauty of the desert. Here you can see the curvature of the earth, the black rock of the Black Rock Desert, and the start of the two forks of the rest of the desert.
The painted mountains to the north will capture your imagination, and the expanse of sky will awe you.