Can I get a transiti visa if I plan to stay 3 days only in Bejing?

I will be traveling through Asia and I came with the idea to stop over in Beijing and know the great wall and the forbidden city. I hold a Mexican passport and according to several Chinese websites I can be up to 72 hours (3 days) with a transit type which allow me to get around the city only, and I am just happy with that. Please let me know if I do need another one for a very short tourist visit.