Photography has the unique ability to capture moments that transcend time and speak to the very essence of human experience.

Some images evoke emotions, spark social change, or challenge the way we view the world. Here are five of the most powerful photos ever taken, each one leaving an indelible mark on history.

1. Diego Frazao Torquato

Diego Frazão Torquato, 12 years old Brazilian playing the violin at his teacher’s funeral. The teacher had helped him escape poverty and violence through music.

2. Terri Gurrola is reunited with her daughter

Terri Gurrola is reunited with her daughter after serving in Iraq for 7 months.

3. A firefighter gives water to a koala

A firefighter gives water to a koala during the devastating Black Saturday bushfires in Victoria, Australia, in 2009.

4…at the grave of her owner

A dog named “Leao” sits for a second consecutive day at the grave of her owner, who died in the disastrous landslides near Rio de Janeiro in 2011.

5. Heart surgeon

Heart surgeon after a 23-hour-long (successful) heart transplant. His assistant is sleeping in the corner.