14 January 2000: The Dow peaks at the height of the dot-com mania

The Dow Jones Industrial Average closed at a record 11,722.98. Investors were euphoric, the economy was booming and the new millennium had arrived without the feared computer meltdown. It would take until October 2006 for the Dow to close higher again. The broader tech bubble kept inflating for a few more weeks, but for the old blue chips, this was the top. Nobody rang a bell.

The lesson: Market tops are usually announced only in hindsight, on days when everything feels fine.