Just a short walk from Rehavia lies the "Valley of the Cross" - Emek HaMatsleva, in my eyes - one the most beautiful outdoor spots in the city, and my personal go-to place to relax. This park is wide, green and hilly, and provides beautiful view points on the whole area. It won't be hard to find the valley's most significant monument - the Monastery of the Cross. Beautiful to look at from a distance, or take a short walk and explore from within. My personal recommendation - grab a blanket, food and your favorite traveling buddy - and find my favorite bench in Jerusalem (walk west, up the valley, on a path leading to the Israel Museum).
עמק המצלבה,, Jerusalem, Israel