Ayutthaya has been classified as part of the world heritage sites list (UNESCO), and I dont see how this decision could be contested. The dozens of temples in ruins that we can visit in the old capital also became ones of the most famous symbols of Thailand.
Yet, the site is surrounded by a river that was a natural defense for the city against potential attacks from rival kingdoms. This river is ironically today the biggest threat to the remains of Ayutthaya. During the rainy season and in exceptional moments in the year, the river leaves its bed and will slowly join invade the ruins. This is one of the most beautiful face of the old capital, but sadly the most dangerous ones for the temples.
Wat Chaiwatthanaram is especially exposed, as located along the river. Local authorities decided therefore to build a removable dam, than will protect the large complex without impacting the beauty of the site.
The old Buddhas who lost their heads will hopefully sleep peacefully for some additional centuries.