From a Denver Post report at the link below:
The Rockies and the Cubs, the two teams with the worst records in the National League, played a 16-inning, 6-hour, 27-minute marathon that began Tuesday night and finished in the wee hours of Wednesday morning at Wrigley Field.
It was the longest game, by time, in history for both franchises. The previous longest game in Colorado history took 6:16 in a 22-inning game at San Diego on April 17-18, 2008.
Full report here.