An experimental broadcast, and a proposal by Philips of the Netherlands, was a 567 line television system for Europe, running at 50 fields (25 frames) per second.
Most of the technology was to be borrowed from NTSC, the difference from NTSC being the reducing of the horizontal scan frequency from 15750 to 14175 Hz.
This would have meant that the NTSC sound carrier frequency of 4.5 MHz above the picture carrier, would have also been the standard for Europe, and hence been a lot more common world wide.
The proposal was defeated as Russian engineers had already shown how NTSC could be easily adapted to a higher resolution by breaking with NTSC bandwidth restrictions, and moving the sound carrier up 2 MHz from 4.5 to 6.5 MHz, along with 625 line scanning.