Spanish Steps, Trevi Fountain and the Pantheon

I still don't get the Spanish Steps.  We came off the subway and turned the corner and there were hundreds of people sitting on some steps.  Chad said "I wonder what is going on?"  I said "I am sure it is lunch (they close their shops for 2-3 hours in the afternoon) and people are just waiting for everything to open up again."  Both of us were wrong, these are the famous Spanish Steps.  I am not sure why they are a tourist attraction.  Any way we sat on the steps and ate our lunch even though we found out later that you really aren't supposed to eat on them.  Oh well they are on the way to Trevi fountain which is definitely worth seeing.  Although it was also crowded (what in Rome isn't crowded) it is really pretty.