Stanley J. Forman 
This picture was shot for the Boston Herald by Stanley J. Forman, in 1976. A fire broke out in Marlborough street and Stanley climbed the firetruck to take this picture. There was universal debate at the grim picture. Despite a great effort the fireman was seconds away from saving their lives. Stanley took this picture but turned away before the young woman Diana Bryant and her godchild Tiare Jones hit the ground. Diana died later that night but broke the fall of Tiare who lived. This controversial picture led Boston authorities (and others worldwide) to re-look at their fire safety codes and improve them. Stanley won the Pulitzer that year, he also happens to be the only photographer to win the Pulitzer in two consecutive years for photojournalism.
Next year he won it again for “Soiling of the Old Glory”, shot near Boston’s city hall, showing Theodore Landsmark, an African-american lawyer who on his way to a case encountered over one hundred and fifty anti-busing youths from South Boston and Charleston protesting the decision to bus in students from Roxbury, an African American suburb.
Nick Ut 
This is perhaps the most famous picture from during the Vietnam War. This picture shows Phan Thi Kim Phuc who was aged about 9, running away from her village which was bombed with Napalm. She was screaming “nong qua nong qua” – too hot too hot. After the picture, Nick promptly took her and other children to the hospital . Nick won a Pulitzer and the World Press Photo for 1972. Kim Phuc was treated and grew up to be a doctor and now lives at Canada. She was also awarded as a goodwill ambassador by UNESCO.
Oded Balality 
Most of my memorable pictures have been longer back in history, as they keep getting repeatedly published and hence more chance of people seeing them. This picture however is from recent times, at Israel. This picture titled “The Power of One” shows a lone Jewish settler challenging Israeli security officers during clashes that erupted as authorities cleared the West Bank settlement of Amona, east of the Palestinian town of Ramallah. This picture taken in Feb 2006, won Balality the Pulitzer in 2007. This picture reminds me of the great photo at Tiananmen Square, coming next.
Stuart Franklin Magnum 
Tank Man or the Unknown Rebel, the one man who stood in front of advancing tanks during Tiananmen Square protests near Beijing in 1989. He held two bags in each hand and stopped the tanks. In response, the front tank tried to go around the man, but he would step into its way and not let it pass. The tank driver refused to crush the man. He later climbed on the tank and spoke with the driver and asked them to “Go away and stop killing my people”. He was pulled into the crowd by onlookers, Sunday Express claimed the identity of the man as Wang Weilin, a 19 year old student. There are various versions about what happened next, some say he was executed, some say he still lives. Many photo versions of this incident exist, the most popular was shot by Stuart Franklin who won the World Press Award and this photograph was featured in Life’s “100 photos that changed the world”.
Source: wikipedia, life.com