For a short while, bicycles took over Dubai ’s busiest highway on Sunday as part of an annual ride marking the city-state’s yearly fitness challenge. Thousands of cyclists rode down the 12-lane Sheikh Zayed Road on the weekend morning. Authorities shut down a portion of the expressway for the Dubai 30x30, a challenge that calls on residents of this sheikhdom in the United Arab Emirates to get 30 minutes of exercise each day in November.