Yes, it is possible to build a brick fire pit without mortar. This type of fire pit is known as a dry stack fire pit. It is a simple fire pit using only bricks that are stacked tightly together. You will need to choose the right type of bricks, such as fire bricks, which are designed to withstand high temperatures. You will also need to dig a shallow hole for the fire pit, level the ground, and lay a foundation of gravel or sand. Of course, you can also substitute the mortar for polymeric sand as shown above as well.