Unbuilt Architecture and City Plans

[Rhinocrates]

Mentions of Boullée already. Here's a good accessible article on his work and milieu.

Designing the Sublime: Boullée and Ledoux’s Architectural Revolution

As dissatisfaction with the old regime fermented into revolutionary upheaval in late-eighteenth century France, two architects cast off the decorative excesses of the Baroque and Rococo styles and sought out bold, new geometries. Hugh Aldersey-Williams tours the sublime and mostly unrealized...

publicdomainreview.org

 

[Jason Dykstra (Wyvern)]

The rather tortuous development of proposals for a canal between Malta's two major ports which never came to be:

History - The canal/tunnel proposals to connect Grand Harbour and Marsamxett

Different variations of the project were proposed over the years

timesofmalta.com