Concrete blocks were first invented, first made in the early eighteen hundreds. Of course, concrete in its' many forms has been around since the ancient Greek times. I believe that concrete was used in the manufacturing of Parthenon, if I'm not mistaken. Go look that up. The first house that was built using concrete blocks was actually in Staten Island, New York, I think in eighteen thirty seven. But, the actual formula of the concrete that we use today was pretty well refined by that time, and they used wooden frames to mold the bricks, the blocks and in much the same way that bricks were made. In fact, in the eighteen sixties there was a company in Chicago that started to form concrete into shapes essentially, where prior to that you would see older homes that had been used stone carving techniques to create these shapes, think gargoyle's and such. But, this company in Chicago actually came up with ways to form the concrete into shapes and save a lot of time and money over stone carving. In fact, a lot of those structures that were built with those stones, the great fire of eighteen seventy one in Chicago, there are still some concrete forms that have survived since that time. So, it's obviously became a great boon to construction when you could build a structure out of concrete blocks, saved a lot of time, a lot of money in the construction phase because you weren't using wood for the main structure of the building, you had a lot less risk of losing everything in a fire. And, we still use to this day basically, the same kind of concrete blocks that were first invented in the early eighteen hundreds.