As part of her Jubilee tour of Wales, the Queen has returned to Aberfan - a Welsh village devastated by a landslide disaster in 1966.
116 children died when a pile of spoil from a coal mine slid down a hill and swamped their school.
Spoil is the waste earth and stone that's dug up when coal is mined.
The tragedy shocked the world and the Queen has visited the community four times since the disaster.
On this visit, to mark the Queen visited a memorial garden and officially opened the village's new primary school.
She also attended a church service and met people from the village.
In Leah's report she explains what happened in Aberfan in 1966.