While Siem Reap is rapidly growing with new luxury hotels, trendy restaurants and stylish boutiques, it retains a small-town character. When I recently visited for the first time in fifteen years, I was amazed at how it has changed—and how it hasn’t. The scale and sophistication of the temples remain simply awesome. Whether you approach the grandest of all monuments, Angkor Wat, at sunrise from the backside with no other tourists in sight or bike out to a remote rural area and hike into a hidden...