The Top one is a barrel Cactus close up, and it is extremely slow on the grow. This one is already 15 years of age, and still not very big.
The next two are Prickly Pear Cactus and are Native to Canada and the United States. This variety comes from Mexico so he has to be brought in for the winter. There is a second Type in the pot as well. A little friendlier as his thorns are only a half cm long. The next picture is that of two more types in the same container, neither of which I know much about and they are wonderful on the patio. The second last one is that Barrel Cactus again but now you can see all of him. and the last one is of that big guy close up with a new pad just starting to grow.