My Son Sanctuary tour, at first light.

For about two hours you walk the tower groups with an English-speaking guide. The trees drip, the brick glows red in the low light, and the paths are still quiet.

At 9:00 AM you sit down to a Champa brunch at a local restaurant, with a mochi cake and fruit, and by 10:30 to 11:00 AM you are back at your hotel with the whole day ahead of you.

The towers are fired brick with stone pillars and sandstone carvings of Hindu myths, built above all for Shiva, and UNESCO calls the monuments unique and without equal in Southeast Asia.

The valley is closed by mountains and fed by the sacred Thu Bon river, which flows on to the sea near Hoi An, the old port of the same coast. A morning here is a morning in the heart of a lost kingdom.

The early start is the other theme. Guests who took the dawn trip write that there were barely any people at the sanctuary, that the air was still pleasantly cool, and that they never felt rushed between the towers.

Food and organisation round it off: guests mention a vegetarian meal arranged on request, smooth pickups and transport. One reviewer also reminds others that drinks and the entrance ticket are not included in the price.

At Da Nang's station, February to April average 7 rain days a month, while June's daily high averages 34.9 °C. March is singled out by the tourism authority as an excellent time to visit.

The tour runs all year, in most kinds of weather. In the hot months, the dawn option is the comfortable choice; in the wet months, it has you back in town before the afternoon.

Da Nang averages 658 mm of rain in October over 21 rain days. UNESCO lists flooding and high humidity among the risks to the site itself. Bring rain gear and shoes with grip.

Bookings refund in full until a day before pickup, so pick a date and keep an eye on the storm warnings. If a storm is coming, move the trip rather than walk the towers in it.

Only the specific afternoon boat option comes back on the Thu Bon River; the plain afternoon option returns by bus. Pick the version you want when you choose your time.

Neither includes the gate ticket. Bring cash: the site's board, in a notice dated 1 January 2019, lists 150,000 dong for foreign visitors.

Look for the details as well as the towers: the sandstone reliefs of Hindu myths, the carved brick on the walls, and the doors of the main shrines, which mostly face east.

Keep to the paths for your shots and never climb on the ruins. Some parts of the buffer zone may still hold unexploded ordnance from the wars.

Bring cash for the ticket, water, sunscreen and, from October to February, an umbrella or raincoat, as other operators advise. Keep your phone charged: the operator needs a working WhatsApp number at pickup.

On the dawn trip you eat after the towers, so a small snack in your bag does no harm before the 9:00 AM brunch.

That matters at My Son more than at most sights. The ruins tell little without the story of the kings, the gods and the war, and the guide is the one who tells it over about two hours on site.

If you prefer to go without a tour, the site's board offers its own guided route of about 60 minutes; one guide ticket covers a group of 1 to 5 visitors.

An Old Town Ticket gives entry to five heritage buildings, and the tourism authority says the old town really comes into its own after dark, when thousands of lanterns light the streets and the river.

On the 14th day of every lunar month the lantern festival dims the town's electric light, a fine end to a day that began among the Cham towers.

Pickup is free within Hoi An town and to the beach; from Da Nang the shared trips charge 300,000 dong each way. The private option picks up in both cities.

Finally, remember what is extra: the gate ticket, paid in cash, and any drinks. With that in mind, it is a well-reviewed way to see the Cham towers.