Located near the Royal Palace, Wat Ounalom is the most important wat in Phnom Penh.
Established in 1443, Wat Ounalom is the center of Cambodian Buddhism. The main complex houses a stupa that contains what is believed to be an eyebrow hair of Buddha and an inscription in pali.
While I couldn’t find the exact wall and window shot in this photo, you can use Google Maps to make a walk inside the enclosure of Wat Ounalom (and maybe find the exact window, but the photo was shot in 2007 and Google Maps is dated 2014, many things could have changed in 7 years!).