<!DOCTYPE html>
<html>
<head>
Aruidno Robot
</head>
<body>
<a href="https://www.arduino.cc/"
<img src="https://store.arduino.cc/bmz_cache/a/aed439071edd4b58c838235c7d91a5d5.image.447x354.jpg" /> </a>
<a href="http://makezine.com/">My Favourite DIY website!</a>
</body>
</html>
your anchor opening tag:
<a href="https://www.arduino.cc/"
it seems to miss the >
to mark the end of the tag.