What is lintel? how many years ago was the pyramid of cheops built?

A lintel is a horizontal support of timber, stone, concrete, or steel across the top of a door or window.  

The Pyramid of Cheops was built 4,500 years ago.

A horizontal support of timber stone concrete or steal going across dors or windows and the pyramid of cheops was buit 4,500 years a go

based on the images pictured above, the major difference between the two cathedrals: the cathedral of notre dame and the amiens cathedral, is that the cathedral of notre dame emphasizes the horizontal lines while the amiens cathedral emphasizes the vertical lines.