<style>
.container { 
    width: 200px;
    height: 100px;
    background-color: red;
    margin-bottom: 300px;
}
.float {
    float: left;
    width: 200px;
    height: 200px;
    background: green;
}
</style>
<div class=container></div>
<div class=float></div>