These old churches were built entirely without nails—and their sturdy construction has stood the test of time http://on.natgeo.com/2xpZN1a

These old churches were built entirely without nails—and their sturdy construction has stood the test of time http://on.natgeo.com/2xpZN1a 

https://twitter.com/NatGeoTravel/status/910866213051478019