The sky is a very important component of the landscape that has been lost in our modern, overcrowded, and excessively illuminated cities. However, this was not the case in the past. Astronomy played a highly relevant role in urban planning, especially in the organization of sacred spaces which were later surrounded by extensive civil urban areas. Today, archaeoastronomy approaches the minds of our ancestors studying the starry landscape and how it is printed in the terrain by the visualization and the orientation of sacred buildings. The sun was indeed the most important component of that celestial landscape and was the primary focus within a large set of unique cultures of great historical significance. In particular, we will study and compare the case of three sun cities: Thebes (Belmonte et al. 2009, Belmonte 2012), Hattusha (Gonzalez-Garcia & Belmonte 2011), and Petra (Belmonte et al. 2013), capitals of Egypt in the Middle and New Kingdoms, the Hittite Empire, and the Nabataean Kingdom, respectively. We will briefly discuss each of these cultures and will scrutinize their capital cities, showing how their strategic geographical position and orography were of key importance, but also how solar observation, and related hierophanies, played a relevant role in the orientation and location of some of their most significant monuments. In particular, we will focus on the great temple of Amun-Re in Karnak, Temple 1 in Hattusha (presumably devoted to the Solar Goddess of Arinna), and the “Monastery” at Petra.