From a Saturday night Associated Press report (emphasis mine):
The first couple took full advantage of the cool spring night.
After a date night out on Saturday evening, President Barack Obama and first lady Michelle Obama decided to take a stroll when their motorcade arrived back at the White House.
So they began walking on the driveway of the White House South Lawn while holding hands. First they passed the West Wing, then their children’s swing set. They kept walking, swinging their hands together.
There were no Secret Service agents right behind them — the agents stood off, in one of the rare moments that the Obamas had private space outside the White House walls.
As the Obamas walked behind shrubbery and out of sight, the unscripted moment left reporters guessing where they were going. To the vegetable garden? The basketball court? No final word, but they eventually came back the same way from where they started, rounding out their 8-minute walk.
And an accompanying photo by Haraz N. Ghanbari: