Photo taken on May 23, 2013, in Zagreb, shows a Croatian citizen signing a petition calling for a referendum to introduce a constitutional clause describing marriage as a "life-long union of a woman and a man." As many of its future EU partners, Croatia, set to join the 27-member bloc on July 1, rumbled on June 12 with calls for a referendum that would prevent same-sex marriages in the largely conservative country. A Catholic Church-backed group holds a march in Zagreb on June 14 to parliament to present the petition calling for a referendum on barring same-sex marriage. AFP PHOTO / STR