There is a photo contest by 
Every week on Sunday a new round starts and the motto is announced.
To participate, you have to publish a post according to the theme, then leave a comment and a link in the contestpost and use the tag #pobphotocontest.
There are POB tokens to be won, which will be distributed as rewards for the published post.
Also 
So it's worth joining in there.
This week's theme is buildings and here is my contribution.
This is the cathedral from Strasbourg. When it comes to buildings, churches are always impressive. Even though I don't like the institutional church, they were able to build buildings. But they are often built on the blood of others.