I've seen some Wats out in the countryside where the families actually had to maintain the wall. This particular temple had the niches all around the perimeter stretching about 100 meters, but the entire wall was in disrepair and falling down in places. Some urns visible and many photo plaques falling off. Most that were in bad shape had very old photos and memorial statements. I would imagine there comes a point when no family left to help maintain things. Pete
