GREAT SITE!
Rome with steam engines? Lots of coal mines? One thousand years of coal and global warming and it never seems to be different, year to year, unless you read the oldest scrolls and believe that things were different, once upon a time.
1. Lots of sea travel, harbors, less land far from water transport in a river or lake or inland sea. Not as much lowland for canals, of course.
2. The Americas, Australia, etc, no longer isolated by climate and crop gaps. Crops exchanged all over the world a long time ago. More tree crops?
3. Lots of big islands that are hard to conquer by expansionist empires. You need to build a navy as well as an army to get anywhere.