We can find ETF that usually mimick some stock index, for e.g. SP500 has SPDR, Dow Jones Industrial Average has DIA, etc.
Does an ETF that tracks all these indexes exist?
If the objective is to mimick all the world's equity stock markets in a single ETF there would appear to be 2 choices:
VT which tracks something called FTSE Global All Cap Index with a very low expense ratio
ACWI tracks the MSCI All Country World Index; it is very liquid