DIVs with CSS powered aspect ratio. Based on the following stackoverflow answer http://stackoverflow.com/a/12121309/1337100

index.html

<div class="wrapper">
    
    <div class="content">
    
    </div>

</div>

main.less

@height = 9%;
@width = 16%;


.wrapper{
    width:100%;
    display:inline-block;
    position:relative;

    &:after{
        padding-top:@height/@width * 100%;
        display:block;
        content:'';
    }

    .content{
        position:absolute;
        top: 0; bottom: 0; right: 0; left: 0;
        //background-size:cover;  // optional
        //background-color:red;   // optional
    }

}

    

Demo here: http://jsfiddle.net/xc2fbnzb/