The axis of Uranus is tilted almost into its orbital plane. To compare this to Earth, instead of a small polar region roughly 23 degrees from the poles, the majority of Uranus would be polar regions. And these polar regions would have 42 years of dark and 42 years of light. This orientation turned out to be fortuitous. In 1977, while watching Uranus occult a star, the ring system of Uranus was discovered.
Occultation occurs when a planet moves in front of a star.
Astronomers time how long the planet is in front of the star in order to determine the radius of the planet. Because of the orientation of Uranus, the rings caused the stars light to blink on and off nine times before the planet blocked the star and nine times after the planet blocked the star. Since the pattern of these nine occultations were mirror images we knew the culprits must be rings and not moons. When Voyager flew by Uranus it verified the existence of these rings. In addition it discovered several moons orbiting Uranus.