In the heart of Los Angeles, on a stretch of Santa Monica Boulevard once dominated by car lots and billboards, a chrome-plated diner glows like a portal to another time, a retro futuristic timeline.

As of early August, the diner's menu has been whittled down to five sandwiches, two sides, two pies, shakes and soft drinks, according to an Eater report. A chef at the restaurant told Eater that the ...