I see similar arches of Cultural Foundation building from my window, so it was obvious choice for me. 

The first sketch is on a scrap of printing paper, but I learned my lesson not to waste good paper as sketch will never look good anyway. Actually any kind of paper or surface is good for sketching.

And I’m glad I played with colors beforehand and I love the color pallet I came up with.

I think I like this unfinished version more than final one. 
And the final one is

For me it has early morning feeling.