Simplify the following text for a Grade 10 native English-speaking person.
Original: The Antonine Wall is a stone and turf fortification built by the Romans across the Midlands of Scotland , between the Firth of Forth ( near modern Edinburgh ) and the Firth of Clyde ( near Glasgow ) .
Simplified: The Antonine Wall is a stone and turf fortification built by the Romans across what is now the Central Belt of Scotland , between the Firth of Forth and the Firth of Clyde .