The lifts are the transport system
Monaco is 2.1 km² and you can walk across it in twenty minutes — but it is stacked in layers up a limestone cliff, and the difference between the harbour and the upper town is a serious climb.
The answer is a network of public lifts and escalators cut through the rock, open long hours and free to use. They are signposted, they are on the maps, and most visitors walk past them and take the stairs instead.
Learning two or three of them turns a hilly country into a flat one.
Trains, buses and the border
The railway station is largely underground, cut into the rock, with exits at different levels of the city — take the right one or you will climb.
Local buses run the length of the country and across the French border. Monaco is not in the EU customs union but is in Schengen; there is no border check, and you will cross into France without noticing.
Do not drive in. The streets are narrow, parking is structured and expensive, and the country is smaller than the walk from most car parks.
On foot
Everything in this guide is walkable from everything else. The distances are trivial; the gradients are not.
Footwear matters more here than in any other city on this network.
Monaco-Ville
Port Hercule
Fontvieille