The "Big Four Sonisphere" tour, featuring Metallica, Slayer, Megadeth and Anthrax, has added two more stops to their European trek. The all-star metal tour will now also make its way to Sofia, Bulgaria, on June 22 and Istanbul, Turkey, on June 27.Metallica commented on its website about the two new shows: "Both shows will include the Big Four of 'Tallica, Slayer, Megadeth, and Anthrax along with very special guests Heaven & Hell.""There is one more Sonisphere show on the calendar," the band added. "We'll be back here with the details shortly."The upcoming tour dates are as follows:3/5 Estadio Mateo Flores Guatemala City, Guatemala
3/7 Saprissa Stadium San Jose, Costa Rica
3/8 Plaza Figali Panama City, Panama
3/10 Park Simon Bolivar Bogota, Columbia
3/12 La Rinconada Caracas, Venezuela
3/14 Coliseo de Puerto Rico San Juan, Puerto Rico
4/13 Telenor Arena Oslo, Norway
4/14 Telenor Arena Oslo, Norway
4/17 Riga Arena Riga, Latvia
4/18 Saku Suurhall Tallinn, Estonia
4/20 Siemens Arena Vilnius, Lithuania
