Ra's ancient city is probably much older than this, but the 2nd and 3rd Dynasties of Egypt's Old Kingdom are when we first see it mentioned in texts. Egyptians called it Iunu, or "pillar city," after its many obelisks. Greeks called it Heliopolis, or "city of the sun." Today, it is still called Heliopolis, and it's a suburb of Cairo.
Solar power was important to the pharaohs of Dynasty 4. They created pyramids (symbols of Ra's power), and carved magical texts (called Pyramid Texts) inside. These texts showed how they could rise to the sky after death and become like Ra. During life, they were the first kings to call themselves Sa-Ra, the Sons of Ra, and introduced a second royal name to show this to everybody.
Userkaf, the first king of Dynasty 5, built a new kind of temple. It was outside, with a small obelisk, and dedicated to Ra. Kings after him liked these sun temples so much that they built lots of them near their tombs and pyramids at Abusir and Abu Ghurab, near Cairo.
During the Eleventh Dynasty, there was a split. In northern Egypt, Ra was King of the Gods. In southern Egypt, Amun was King of the Gods. This wasn't a problem until both parts of the country had royal palaces. During Dynasty 11, when the rulers were coming from the south instead of the north, both gods merged, like a giant solar Voltron, to become a new god, called Amun-Ra.
These big stone needles that look like a tiny pyramid on top of a giant square pillar are supposed to be symbols of sun rays. During the New Kingdom, they got bigger and much fancier. Dozens of obelisks were put up at the temple of Amun-Ra at Karnak (in Luxor, Egypt). Many of these are now in Rome or other cities around the world. One, the biggest of all, never left its quarry in Aswan—it cracked while they were carving it, and so they left it in the ground. (Source.)
During Dynasty 18, a pharaoh, born with the name Amunhotep, decided he didn't like the Amun-Ra version of the sun god. For him, the sun itself, called Aten, was much more interesting. He changed his name to Akhenaten ("the shining one of the sun"), and even moved the capital of Egypt to a new city, where only Aten worship was permitted. Unfortunately for Akhenaten, this wasn't very popular, and after he died, things returned to normal.
During the Late Period Egypt, Ra had a sacred bull called Mer-wer (or Mnevis in Greek). Only completely black bulls could be dedicated to Ra this way, and they were sacrificed (beef brisket, anybody?) and then mummified at the temple of Heliopolis in Ra's honor. No bull! (Source.)
Each morning, Ra's boat, sometimes called the Boat of Millions of Years, starts to climb the sky as it heads from sunrise to sunset. Each morning, Apep, the serpent of chaos, tries to stop Ra from rising, and various gods destroy it, and literally save the day. But chaos is not easy to get rid of, so every morning, it happens again. Each red sunrise is Apep's blood, from Seth's spear or Isis's chains or other gods' knives, and proof of good triumphing over evil.