Concrete on the roof?

What do you think these workers are doing?
https://teakdoor.com/Gallery/albums/u...l_DSCN3282.jpg

Here is a hint.
https://teakdoor.com/Gallery/albums/u...l_DSCN3265.jpg

Making a little coffee shop for tourists who are waiting to see the boys in brown??

Looking for drug dealers who are supposed to be hiding under the roof tiles, but they're too stupid to go inside and look?

Painting the tree's a lovely natural shade of green?

Building a tourist prison?