I've tried reading:

[What is the purpose of .row in Bootstrap?](https://stackoverflow.com/questions/39960679/what-is-the-purpose-of-row-in-bootstrap) and <http://www.helloerik.com/the-subtle-magic-behind-why-the-bootstrap-3-grid-works>

However, none of of them explains why my columns in the following code do not float left:

```
<div class = "container">
    <div class = "col-2">
        1
    </div>
    <div class = "col-2">
        2
    </div>
</div>

```