The world's population has today reached 8 billion.
The estimate is from the United Nations and other experts.
More people living longer has led to rapid growth recently, however that’s expected to slow.
Taiwo Shemede runs a school in Makoko on the coast of Lagos, which is predicted to become the largest city by the end of the century:
"We have 200,000 people living on water and we have 2,000 people living on lands right now the kids the children are more than the adults know most people don't even want to have a child anymore."
