After China's 9% decline in their stock market, stock markets all over the world fell too. The US stock market indexes fell over 3%. (It fell over 4% at one point, but this was blamed on a computer glitch.) Several people reported being locked out from trading.
Barry Ritholtz wrote back on December 27, 2006, that we had -- at that time -- in the stock market's history.
The long-awaited correction has now happened. What remains to be seen is whether there will be a further correction or whether this has wrung the excess out of the market.