Later glacial action had further dramatic impact on the scenery. Today, this coast-to-coast straight valley allows easy passage for road and canal communications. Evidence of the glaciers which shaped the rugged landscape can be seen in Glen Roy, north of Glen Spean, where the famous landscape features known as the Parallel Roads are ancient shorelines of glacier-dammed lochs.

The Caledonian Canal in the Great Glen links three natural lochs and was completed in 1822. Today it is mostly used by leisure craft (cruises and watersports available). Both the Great Glen Way (for walkers) and the Great Glen Cycleway run parallel to it and in places use the towpath.

Glen Spean carries an important east-west route to and from Speyside. Spean Bridge (woollen mill here) stands at its junction with the Great Glen. The area around Spean Bridge and the southern end of Loch Lochy (one of the three lochs in the Great Glen) is rich in associations with the Jacobite clans and the uprising in 1745. This is also one of the themes of the Clan Cameron Museum at Achnacarry Castle near the south west end of the loch.

A more recent theme also explored at Achnacarry is the use of the area as a training ground for Commandos during World War II. The well-known and very moving Commando Memorial stands near Spean Bridge, while the museum at Achnacarry, their training HQ, is also the starting point for the Commando Dark Mile Trail. (The Dark Mile itself is a very old name for a stretch of the B8005 between Loch Lochy and Loch Arkaig to the west, referring to the dense trees which once grew there.) This trail points out some of the main training places for these forces. (The Chia-Aig Falls, one of the locations in the movie "Rob Roy", are also at the far end of this stretch of road.)

Further north and west, the Glengarry Visitor Centre exhibits local history as well as the area's connection with Glengarry, Canada.