In the late 1980's, when I was at college in Sydney, we had a visit from a chap (I think from somewhere in the north of Europe) who'd previously won a tender for, IIRC, a booking / tracking system for a relatively small airline, all to be written in Turbo Prolog.

I recall two key things from his presentation of his final product.

First, he claimed he'd quoted a half the cost/time of a COBOL-based, and a quarter of a C-based, competing tenders -- and that he'd met his deadlines.

Second, the UI was just beautiful - for both aesthetics and performance.

I didn't have much experience in enterprisey software at the time, but what little I had seen was archetypal terminal-style, monochrome, sluggish, far from user-friendly etc. I have some (no doubt unreliable) memories of this thing looking like a 'modern' (say Amiga) GUI app.

Another item in that large category of 'I wish they'd drop these things into the public domain once they retired it from production' as it would probably still make a great demo (though most free Prolog implementations these days wouldn't support (m)any of the pretty Turbo extensions, I'm sure).