The Zero Hour reference article from the English Wikipedia on 24-Apr-2004
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Zero Hour

In 1994 DC Comics decided to publish a four-issue crossover limited series (numbered in reverse order - it began with issue #4 and ended with #1).

That series, in some ways a repeat or aftermath of Crisis on Infinite Earths, featured most of the characters published by DC at the time. It retconned a number of things on the DC Universe continuity, and also served to launch and end a number of ongoing series. All DC comics published immediately after the end of the series had a #0 issue (both limited series such as Xenobrood, new series such as Fate or already existing series such as Aquaman).

Series finished during or because of ZH

Series launched during or because of ZH

The limited series Xenobrood was launched at the same time, but did not really have a ZH connection.