Illinois is the sixth state to allow civil unions or their equivalent, which provide same-sex or opposite-sex couples the same state-level rights as married couples. Wednesday was the first day couples could get civil union licenses and, as with marriage, there is a one-day waiting period before a ceremony can be held.

Outside one of the park entrances Thursday about a half-dozen protesters stood quietly, holding a sign that said: "Marriage. One man. One woman." The protesters were part of the recently formed Illinois Defense of Marriage Initiative, which is trying to gather at least 300,000 signatures to put an advisory referendum measure on the 2012 ballot that would oppose the civil unions law.