You are looking at one of the most deliberate sightlines on Earth. Start at the Louvre and look west. A single straight line runs for roughly five miles (8 kilometers), through the Tuileries Garden, across the Place de la Concorde, up the Champs-Élysées, through the Arc de Triomphe, and out to the skyscrapers of La Défense. The French call it the Axe Historique, the Historic Axis. It started small, as a garden path lined up with the setting sun. Then king after king, and later emperors and presidents, kept building on that same line instead of starting a new one. Nobody ever bent it. Here is the part almost nobody notices. The Louvre itself sits about six degrees off from the true axis. Instead of fixing that when they built the Grande Arche two centuries later, engineers tilted the Grande Arche by that same six degrees, in the opposite direction, on purpose. Two buildings, three hundred years apart, quietly lining up across five miles of Paris. Twice a year, the sun sets in perfect line with the Arc de Triomphe when you look down the Champs-Élysées. Parisians have a name for it: Parishenge. It is a bit like standing at the Lincoln Memorial and looking straight down the Mall to the Capitol, except this line is older, longer, and nobody planned it in one sitting. It grew that way over centuries and somehow never went crooked.