The hook
The temples of a vanished empire spread across the jungle near Siem Reap: the largest religious monument on earth, a bridge of stone gods, faces carved into towers, and a ruined temple strangled by the roots of giant trees.
01Why it's worth it
Angkor was the capital of the Khmer Empire, which dominated Southeast Asia for centuries, and at its height its city may have been among the largest in the pre-industrial world. What remains is one of the greatest concentrations of monumental architecture anywhere: Angkor Wat itself, a colossal temple-mountain surrounded by a moat and covered in bas-reliefs, the largest religious monument on the planet; the Bayon, its towers carved with enormous serene faces; and Ta Prohm, deliberately left half-swallowed by the roots of strangler figs, the jungle and the stone locked together. Beyond the famous three lie dozens more temples across the forest, quiet and rewarding. It is heavily visited, and the sunrise crowd at Angkor Wat is huge, but the scale of the site easily absorbs it if you range wider.
02How to experience it
Buy a multi-day pass and go beyond the big three; the outer temples are gorgeous and near-empty. Do Angkor Wat at sunrise, then flip the usual route to hit the popular temples when the tour groups are elsewhere. Explore by bicycle or tuk-tuk, and hydrate; it is hot and vast.
The honest note
The most useful thing said about Angkor in the r/travel Cambodia threads is a warning against letting it become the whole trip. "Most people spend very little time in Cambodia, and the time that they do spend is often visiting just Angkor Wat, and sometimes Phnom Penh," wrote one traveller who gave the country two weeks. "That's a pity, as the country has much more to offer, and arguably is far more interesting away from the tourist centric sites."
Another put the same point as a scheduling regret: having allotted two and a half weeks to Thailand and four days here, they called it "a huge mistake — in my opinion, Cambodia deserves at least equal time," and went back to Siem Reap for three months. Take Angkor as the reason to come and not as the itinerary.