Praying for Babylon

It's easy to pray for those in authority when they are good to us, but how do we pray for those we don't like, or who do us harm? Or is there any obligation to pray for them at all? 

Psalm 137:1-9; Jeremiah 29:4-14; Matthew 5:43-47

By the Waters of Babel, James Tissot, The Jewish Museum, Brooklyn. 

Music: “Rivers of Babylon,” Boney M, Nightflight to Venus, Sony Music, 1978/2007.