top-ranked Model UN team. YIRA also has a Europe-based offshoot, Yale Model Government Europe, other Model UN conferences such as YMUN, YMUN Korea, YMUN Taiwan and Yale Model African Union (YMAU), and educational programs such as the Yale Review of International Studies (YRIS), Yale International Relations Leadership Institute, and Hemispheres. The campus includes several fraternities and sororities. The campus features at least 18 a cappella groups, the most famous of which is The Whiffenpoofs, which from its founding in 1909 until 2018 was made up solely of senior men. Yale's secret societies include Skull and Bones, Scroll and Key, Wolf's Head, Book and Snake, Elihu, Berzelius, St. Elmo, Manuscript, Brothers in Unity, Linonia, St. Anthony Hall, Shabtai, Myth and Sword, Daughters of Sovereign Government (DSG), Mace and Chain, ISO, Spade and Grave and Sage and Chalice, among others. The two oldest existing honor societies are the Aurelian (1910) and the Torch Honor Society (1916). The Elizabethan Club, a social club, has a membership of undergraduates, graduates, faculty and staff with literary or artistic interests. Membership is by invitation. Members and their guests may enter the "Lizzie's" premises for conversation and tea. The club owns first editions of a Shakespeare Folio, several Shakespeare Quartos, and a first edition of Milton's Paradise Lost, among other important literary texts. Traditions Yale seniors at graduation smash clay pipes underfoot to symbolize passage from their "bright college years," though in recent history the pipes have been replaced with "bubble pipes". ("Bright College Years," the university's alma mater, was penned in 1881 by Henry Durand, Class of 1881, to the tune of Die Wacht am Rhein.) Yale's student tour guides tell visitors that students consider it good luck to rub the toe of the statue of Theodore Dwight Woolsey on Old Campus; however, actual students rarely do so. In the second half of the 20th century Bladderball, a campus-wide game played with a large inflatable ball, became a popular tradition but was banned by administration due to safety concerns. In spite of administration opposition, students revived the game in 2009, 2011, and 2014. Athletic Yale supports 35 varsity athletic teams that compete in the Ivy League Conference, the Eastern College Athletic Conference, and the New England Intercollegiate Sailing Association. Yale athletic teams compete intercollegiately at the NCAA Division I level. Like other members of the Ivy League, Yale does not offer athletic scholarships. Yale has numerous