Without any doubts The Last Supper created by Leonardo da Vinci is a main attraction in Milan. It’s so popular that it’s absolutely impossible to see this masterpiece without tickets reservation in advance.
When I was in Milan I tried to buy tickets near the entrance and I need to admit that it was my mistake. You can’t buy tickets to Santa Maria Church (place where the The Last Supper located) there. There are two opportunities to buy the tickets. First is to ask tickets in your hotel. It’s too dangerous since tickets to the Last Supper are limited and they sell very quickly. So, you can ask but there is a great probability that you will give a negative response.
Second, is to buy tickets in advance online. I have prepared a few links for you which you can follow and buy tickets to the Last Supper Online. As for me it’s a most suitable and convenient way to see greatests masterpiece. Enjoy your stay Milan!!!