I've lived in Germany for quite a while and on the autobahn (which is just German highways not a special road) there are long stretches with no speed limit. The suggested speed is 130kph (80mph) which is also the actual limit in most places outside of construction areas or major exits/entrances. You're allowed to go faster in unrestricted areas (more penalties if you get in an accident and are over 80mph though).

On those stretches at first it felt crazy going 100mph but now I can be driving along, not thinking about my speed at all just keeping up with traffic in the center lane and look down and I'm going 105. The fastest I've gone (in my car not designed for speed whatsoever) is about 125; around 115 I felt like I was actually going fast. I've been passed by sports cars (or weirdly fast 90s BMWs) that must've been going 150+.