What does Santiago notice at the abandoned church that he takes shelter in on his way to the merchant?

Santiago is a
shepherd boy who genuinely loves his sheep. He even calls each sheep by name. While he is
traveling through familiar country in Andalusia, he happens upon a dilapidated church that he
has stayed at once before. One interesting characteristic about this abandoned church is that
"an enormous sycamore had grown on the spot where the sacristy had once stood" (3).
Not only that, but there is a fence that keeps the flock in during the night. All he has to do
is lay some planks across the broken gate and the sheep will not run off. 

What is most interesting about the church, however--and what Santiago
notices...