You can watch the sunset twice in one day at the Burj Khalifa.

Standing at 828 meters (2,717 feet), the Burj Khalifa is the tallest building in the world. Its immense height allows observers at the top to see further around the curvature of the Earth than those at ground level. This phenomenon occurs because the horizon line retreats as your altitude increases, extending your line of sight.On a clear day, the time difference between the sunset at the base and the sunset at the 148th floor is approximately three minutes. This delay is so significant that it affects religious practices in Dubai. During Ramadan, the Islamic Affairs and Charitable Activities Department mandates that residents living above the 80th floor wait an extra two minutes to break their fast, while those above the 150th floor must wait three minutes.The physics behind this involves the Earth's radius and the observer's height above the surface. As you ascend, the angle at which you view the sun changes, allowing you to see light that is already blocked by the horizon for people below. The Burj Khalifa's elevators travel at 10 meters per second, which is fast enough to reach the observation decks before the second sunset concludes.This unique vertical perspective effectively makes the day longer for those at the top of the skyscraper. Scientists use similar calculations to determine the distance to the horizon, which for a person at the top of the Burj Khalifa is about 95 kilometers. This demonstrates how architectural scale can directly influence our perception of celestial events.