El Niño — the warm phase of the Pacific ocean-atmosphere system — affects weather globally every 2–7 years.

Some deep‑sea creatures have never seen sunlight in millions of years.

Dolphins surf ocean waves purely for fun — one of the clearest signs of play behavior in animals.

Prehistoric oceans contained giant marine reptiles.

Dolphins have been observed surfing ocean waves purely for fun — one of the clearest signs of play in non-human animals.

The ocean contains structures larger than mountain ranges.

Sharks predate trees by about 90 million years — they've been swimming Earth's oceans for 450 million years.

The deepest part of the ocean is deeper than the height of Mount Everest.

Surfer Garrett McNamara rode a 78-foot wave off Nazaré, Portugal, in 2011 — a record at the time.