Untitled

<!DOCTYPE html>
<html lang="pl-PL">
<head>
<meta charset="UTF-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>iframe</title>
<style>
iframe{border:0;display:block;margin:0 auto;width:100%;height:calc(100vh - 1vw)}
</style>
</head>
<body>
<div style="width: 800px; height: 500px; background-color: tomato;">
<iframe src="https://www.google.com/maps/embed?pb=!1m18!1m12!1m3!1d2440.2785307498157!2d21.02902891616192!3d52.29279887977194!2m3!1f0!2f0!3f0!3m2!1i1024!2i768!4f13.1!3m3!1m2!1s0x471eceb3d7c83799%3A0x7f35a5f27b92ab46!2sLudwika+Kondratowicza+4%2C+Warszawa!5e0!3m2!1spl!2spl!4v1477302566175" class="iframe"></iframe>
</div>
</body>
</html>