"Up All Night" by Zac Peterson. Olin and Uris Libraries at night, from the Arts Quad. This week's Photo of the Day theme is Libraries. Last week's Guess the Building! photo was Martha Van Rensselear Hall. Send your own submissions to lens@cornellsun.com for a chance to have your photography featured as a "Photo of the Day" or in a "This Month in Photos" slideshow on cornellsun.com.