Angkor Wat at sunrise

The crowds gather behind the left-hand reflecting pool before five for the sun coming up over the five towers. It is worth the early alarm once. But the same temple at three in the afternoon, when the tour buses have left for the hotel pool, is nearly empty and the light is gold on the carvings. Do both if you can; skip the sunrise if you can't face the dark.

The temple pass, and pacing it

The Angkor Archaeological Park pass is one, three or seven days, bought at the official ticket office (not from anyone outside it). Two full days is the sweet spot. Angkor Wat and the Bayon faces, then the jungle-strangled Ta Prohm and far-out Banteay Srei. People who try to do it all in one day come away templed-out and remembering nothing.

The weight of the recent past

Phnom Penh's Tuol Sleng and the Choeung Ek killing fields are not sightseeing. They are the memorial to the Khmer Rouge years, and many travellers find them the most affecting hours of the trip. Go quietly, take the audio guide, and don't photograph for show. Cambodia is open about this history because remembering it matters to them.