With the right teacher, any classroom - be it a boat in Brazil or a park in Pakistan - can change a child's life.
World Teachers' Day, a UNESCO initiative highlighting the work of educators teaching children amid intimidation and poverty, is coming up on October 5.
Thanks to international efforts, the number of children not attending primary school has plummeted to an estimated 57 million worldwide in 2015 from 100 million 15 years ago, according to the UN.
Reuters asked photographers to document teachers, their students, and classrooms across the world to celebrate the power of learning. We've compiled the best photos here.