Human attention cycles with a rhythm of about 90 minutes — the same as sleep cycles.

Nothing can travel faster than light in a vacuum.

Fact #2062 · General

Memories are reconstructed each time you recall them.

Fact #1812 · General

The city of Ur was a major Sumerian settlement.

Fact #1647 · General

The 24th Amendment eliminated poll taxes in federal elections.

Fact #1133 · General

There are invisible worlds.

Fact #2312 · General

The Ice Age allowed humans to migrate across land bridges.

Fact #726 · General

Short-term memory typically holds only a limited number of items at once.

Fact #942 · General

Some people wake up during surgery and cannot move or speak.

Fact #2255 · General