Most people would probably answer that the massive tsunami that struck Lituya Bay in Alaska in 1958 was an astonishing 545 meters high. While that tsunami was indeed the largest ever recorded, the actual highest tsunami ever recorded likely occurred much, much earlier.
65.5 million years ago, when a 14-kilometer-wide fireball struck the Gulf of Mexico, the impact caused tsunamis to radiate outwards across the surrounding seas.
According to the latest simulations, the initial waves triggered by this asteroid reached an incredible height of 1.5 kilometers, nearly three times the height of the tsunami in Lituya Bay!
However, this massive tsunami appears to have shrunk to a height of 14 meters as it approached the coast. This was because the Chickscuba fireball struck relatively shallow water; if it had struck the open ocean, it might have generated waves as high as 4.6 kilometers.