Amid the energy crisis of the 1970s, President Jimmy Carter hoped to reduce America's dependence on foreign oil.

Nearly 40 years after President Carter had 32 solar panels installed on the White House's roof, he watched nearly 4,000 of them go up in his hometown of Plains, Georgia, in 2017. The panels were capable of powering more than half the town.

Jimmy Carter helped expand democracy around the world long after he left the White House. His efforts gave rise to the Carter Center, which promotes fair elections as a vehicle for peace.