Bergamo was not on my list of places to visit in Italy before arriving in Italy. After a chat with an Italian who lives in Milan, my husband and I said we should visit Bergamo on our last day in Italy, before our flight (which was in the evening). We assumed that Bergamo is a new city, as it has the airport, but in fact there is an ancient city too and it’s so beautiful it is worth spending at least a day. So, if you are flighting to or from Bergamo, allow for a day to do sightseeing.
I will share a lot of pictures from Bergamo, so you can get a feel of the place. I fully recommend taking the train tour around the city, using both funiculars, and visiting museums too, if you have the time. There are regular trains from and to Milan and these are very cheap. This makes Bergamo great for a day-trip if you are based in Milan too.