I noticed awhile back, that no one seemed to know what happens if you overstay the 90 days that a visa - for the U.S. passport, anyway - allows. Well, being the experimental type ( and a little spacey about dates, etc. sometimes ) I tried to leave Colonia, last Monday, for Buenos Aires. They made me go upstairs, after the agent decided I had stayed 91 days. I had to pay 1,055. UR pesos, cash, and sign paperwork, and then they gave me a very official ( gold embossed! ) piece of paper that I had to hand to the immigration officer. the funny thing is, it took 4 agents to process this, and 2 wanted to just let me off, since it was only 1 day. the other two "won". They were nice about it, and I definitely learned my lesson!?