Beyond pictures
Video and audio play natively in every browser — no plugins. And <iframe> embeds other pages, like maps or videos. Each needs a little care: captions, titles and sizes.
video, audio, iframe
<video controls width="640" height="360" poster="cover.jpg" preload="metadata"> <source src="trek.webm" type="video/webm"> <source src="trek.mp4" type="video/mp4"> <track kind="captions" src="trek.en.vtt" srclang="en" label="English"> Your browser can't play this video. <a href="trek.mp4">Download it</a>. </video> <audio controls src="birds.mp3"></audio> <iframe src="https://www.openstreetmap.org/export/embed.html" width="400" height="300" title="Map of Pokhara" loading="lazy"></iframe>
Avoid autoplay with sound — it startles people and screen reader users can't hear their reader over it.