president trump's key campaign promise, build that welcome and takes a big step forward today. the president toured border wall prototypes during a visit to san diego, california. let's take a look. >> if you don't have a wall system, we are not going to have a country. there is a lot of problems in mexico. they have a lot of problems over there and they have the cartels and the cartels, we are fighting the cartels, and we are fighting them hard. nobody ever thought that mike weir fought them. we are looking at capability and solid concrete on the outside door steel and concrete. the piece that you see a peer or you see more clearly, the larger dress, the better is because it's very hard to get over the top. it is really deter them from getting over the top. who would think? who would think? but getting over the top is easy. these are professional mountain climbers, they are incredible climbers. they can't climb some of these