Ancient people made their own concrete and we can, too. Making concrete at home without ever having to buy a bag of concrete is simpler than you can imagine.
First you need to find the limestone required to make it, which can be found almost anywhere on the planet. To identify limestone is a simple process.
This is an example of what limestone looks like.
Pour some vinegar onto the rock and watch to see if it starts to fizzle, if it does you have found limestone.
The next step is to cook the limestone over a fire, which causes it to swell and become less dense. Allow the limestone to cool off completely.
Next after you have waited for the limestone to cool, pour water onto the limestone which will cause it to hiss and crack. The solid portions will turn into an absorbant poweder which you will mash up.
Then all you need to add is sand, which is found almost everywhere, and some gravel or pebbles. And you have just made concrete that you can use for building or any other project you may have.