No normal Ferris wheel
Technically speaking, the London Eye cannot be called a Ferris Wheel, after George Gale Ferris Jr. who constructed the first such object in 1893. That’s because it is supported laterally, i.e. it rotates on a cantilever. Although it was the tallest Ferris wheel in the world when it opened, there are now taller wheels in Nanchang, Singapore, and Las Vegas, but they are actually Ferris Wheels. Thus, the London Eye can claim to still be the tallest Ferris wheel of its design.