There are three ways to straighten horizons and fix leaning buildings in Lightroom.

1. Use the crop tool to rotate the horizon
2. Use the level tool to draw a guiding line along your horizon or vertical surface
3. Use the Guided transform tool to fix both horizontal and vertical lines at the same time - corrects perspective control too.  Options 1 and 2 do not.

 https://www.youtube.com/watch?v=ErDkU7IzWtU&feature=youtu.be A recent Lightroom update brought a new panel - The Transform Panel with the powerful Guided Transform feature. Learn the ins and out of using the Lightroom Crop tool and the Transform Panel to fix horizons and straighten leaning buildings BUY MY LIGHTROOM SERIES - Save 20% OFF (LIMITED TIME)Visit http://photorec.tv/lightroom/