Simplify the following text for a Grade 7 native English-speaking person.
Original: The Great Glen ( Scottish Gaelic : An Gleann MÃ r ) , also known as Glen Albyn ( Gleann Albainn - the Glen of Scotland ) or Glen More is a series of glens in Scotland running 100 kilometres from Inverness on the Moray Firth , to Fort William at the head of Loch Linnhe .
Simplified: The Great Glen is a series of glens in Scotland . It runs 100 kilometres from Inverness on the Moray Firth to Fort William at the head of Loch Linnhe .