The world's first heavy cruiser - although it was not called that at that time - was a design ordered by the Chinese Navy in 1913 from the Cantieri Navali Triestino yard (together with three much smaller scout/flotilla leader vessels). An obvious development of the Admiral-Spaun-class, the ship would have featured up to 100mm vertical armour, up to 63mm deck protection and machinery for 28 knots. She would have positively bristled with guns; apart from the main battery of four 203mm pieces in twin turrets there were twelve 120mm and fourteen smaller pieces; complement is unknown but must have been huge. All this was to be accommodated on little more than 4.900 tons standard - the size of HMS Bristol - which strikes me as not very realistic. She was supposed to look like this:
She had been barely laid down when Italy joined the war and turned the very yard area to a battlefield. When the Austrians finally managed to drive the Italians out of the Trieste area, there was enough material available to make completion of the ship feasible. She was however redesigned as a standard light cruiser with eight or nine 150mm guns (written sources say eight, but all available images clearly show nine) and two new 90mm HA guns (Conway says nine, but that's certainly wrong). There also would have been two twin 450mm torpedo tubes. All other particulars remaining the same, this looks a lot more realistic than the original.
Events overtook the project, and construction never resumed.