Trees help reduce the "greenhouse effect" by absorbing CO2. One acre of trees removes 2.6 tons of CO2 per year.
Hospital patients heal faster, require shorter stays and less painkillers if room windows face trees.
Two mature trees provide enough oxygen for a family of four.
The Great Pyramid is a stone computer – if you take the lengths of the sides, and their heights and angles, you can calculate many different things. The pyramid will tell you how to work out the distance round the outside of a circle if you know the distance across it.
The pyramids are close to the Nile because some of the huge stones had to be carried from the quarries by boat.
The pyramids are all on the West bank of the Nile – the side on which the sun sets. This is for religious reasons.
Pyramid -builders tried to fool thieves by placing a blocking stone at the end of a passageway and plastering it in. If thieves broke through the plaster then they would come to the stone and give up. The real way into the tomb would then be through a hidden trapdoor in the ceiling.
