I visited Andorra for a long weekend when I was on a long Western European trip. We had just come from Île-de-France and were heading towards a town near Barcelona where my travel partner was from. We met his parents there and spent time in the mountains where we rented a house from AirBnB.
Because of who I was with, my experiences were mostly of the nature that is there rather than civilisation. We hiked around the Pyrenees, including seeing the Llacs de Tristaina in the north-western part of the country and then also the Riu de Jan in the northeast.
The capital city, Andorra la Vella, is in the southeast and you often have to drive through it to get anywhere in Andorra. For example between the Llacs de Tristaina and the Rui de Jan, we had to drive through the capital, which is on the other side of the tiny country. We did not stop and see it but to be honest, my impression driving through was not the greatest. It reminded me of the concrete jungle that resulted from the 1970s. It was not really impressive; we also did not have the time, so it was not a place that I was very interested in visiting.
Something I found very interesting is that you can really only access Andorra from the outside via two roads. The first is in the southeast near the capital that goes into Catalonia. The other goes into southern France and is now a tunnel, the Envalira Tunnel. The old route that goes up and over the mountains still exists but is not used very often. The toll as of 2021 is €4.30 and light vehicles (cars, trucks + trailers up to 3 axels) is €6.80.