<!--16:9 aspect ratio-->
<object>
<div class="embed-responsive embed-responsive-16by9">
<iframe class="embed-responsive-item" src="https://www.youtube.com/embed/IUIHs3nVC5E"></iframe>
</div>
</object>
<!--4:3 aspect ratio-->
<object>
<div class="embed-responsive embed-responsive-4by3">
<iframe class="embed-responsive-item" src="https://www.youtube.com/embed/IUIHs3nVC5E"></iframe>
</div>
</object>