Okay kiddo, so you know how you sometimes take a road trip with your family? Well, there are lots of roads all over the world that connect different places. In Europe, they have something called the European route system, and one of the roads on this system is called E73.
E73 is a really long road that goes through a bunch of different countries in Europe. It starts all the way up in Norway and goes all the way down to Greece! Can you imagine driving that far?
Along the way, E73 goes through lots of different cities and towns, and it's kind of like a big highway that people can use to travel around. Some parts of the road might have mountains or rivers or forests, while other parts might go through big cities with lots of buildings and people.
The road is marked with signs that have a blue background and white letters that say "E73" on them, so people can easily follow it and know they are on the right path. It's really important that people know where they are going and how to get there safely, which is why these signs are there to help!
So, in summary, E73 is a road in Europe that goes through lots of different countries and cities. It helps people travel from one place to another safely and efficiently!