A glance at some sporting events and teams that have been affected by attacks and threats:
Sept. 5-6, 1972 — Palestinians going by the name of "Black September" kill 11 Israeli athletes at the 1972 Munich Olympics.
April 21, 1987 — A car bomb kills more than 100 people at a bus station in Colombo, Sri Lanka. The blast came during a tour of the country by the New Zealand cricket team. The three-Test tour was cut to one.
Feb. 11, 1996 — Cricket teams from Australia and the West Indies refuse to play preliminary World Cup matches in Sri Lanka a week after a huge bomb blast in Colombo killed 80 people and injures 1,200.
July 27, 1996 — Centennial Park bombing at Atlanta Olympics. The attack took place during a nighttime music concert at the Centennial Olympic Park. The explosion killed one person and injured over 100 others.
April 5, 1997 — The Grand National, the most famous horse race in England, was abandoned after two coded bomb threats were reportedly received from the IRA. Sixty-thousand spectators (including Princess Anne), jockeys, race personnel and local residents were evacuated, and the course was secured by police. The race was run two days later.
May 1, 2002 — Hours before the Champions League semifinal between Real Madrid and Barcelona, a car bomb was detonated near Bernabeu Stadium in Madrid. Seventeen people were injured. UEFA made security checks before going ahead with the match.
May 8, 2002 — A suicide bomber killed 14 people outside the hotel where the New Zealand cricket team was staying in Karachi, Pakistan. Fourteen people died in the attack and the New Zealand team returned home.
2006 — Iraqi sportsmen and women were targeted three times. On May 17, 15 athletes and officials of the Iraqi taekwondo team were kidnapped as they headed to Jordan for a training camp. None of the athletes were seen alive again. On May 26, gunmen shot and killed the Iraqi tennis coach and two of his players. The final attack on July 16 involved 50 gunmen who attacked a sports conference in Baghdad. They kidnapped 30 athletes and officials, including the head of Iraq's Olympic Committee, Ahmed al-Hadjiya.
April 9, 2008 — A suspected Tamil Tiger suicide bomber detonated a device at the start of a marathon celebrating the start of Sri Lanka's new year. Highways minister Jeyaraj Fernandopulle, former Olympic marathon runner KA Karunaratne and the national athletics coach, Lakshman de Alwis, were among the dozen people killed.
Jan. 4, 2008 — The Dakar Rally was canceled for the first time in its 30-year history. The threat of an attack from al Qaeda made the race too risky for the organizers.
March 3, 2009 — The Sri Lankan cricket team bus was attacked by masked gunmen as they traveled in their team bus outside a stadium in Lahore, Pakistan. Seven people were killed in the attack and six of the Sri Lankan cricket players were wounded.
Jan. 8, 2010 — Assistant coach Abalo Amelete and communications director Stanislas Ocloo of the Togo soccer team were killed when gunmen fired on the team's bus in Angola, site of the African Cup of Nations soccer tournament. The Angolan driver was also killed and nine members of Togo's party were wounded including Togo's reserve goalkeeper.
April 15, 2013 — Two bombs exploded in the crowded street near the finish line of the Boston Marathon, killing two people and injuring more than 130 others. The explosions occurred about four hours into the race and about three hours after the men's winner crossed the line. By that point, more than 17,000 of the runners had finished the race, but thousands of others were farther back along the course.