Robots of German Nao-team Hulk of the Hamburg University (R- in silver) and from Iran Nao-Team SRC (L-in blue) vie for the ball during a soccer match between two Robot team during the 12th International Iran Open Robocup 2017, in Tehran, Iran on April 5. The event will be held at Tehran's International Fairgrounds from April 5 to 7. More than 2,000 students from 12 countries are set to take part in the three-day contest.  EPA/Abedin Taherkenareh