HTML
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<style type="text/css">
body {
background-color: #000;
}
body,td,th {
color: #FFF;
}
.tooltip { position:relative; z-index:20; }
.tooltip span { display:none; position:absolute; left:0px; top:10px;}
.tooltip:hover {z-index:21;}
.tooltip:hover span {
display:block;
}
</style>
</head>
<body>
<h1>Webseite</h1>
<p> </p>
<center>
<p><img src="Untitled-4.jpg" width="1000" height="1000" usemap="#Map" border="0" />
<map name="Map" id="Map">
<a href="" class="tooltip"> <area shape="rect" coords="1,-1,79,80"> <span><img src="tooltip.jpg" width="300" height="150" /></span></></a>
<area shape="rect" coords="1,-1,79,80" href="https://de.wikipedia.org/" />
</map>
</class>
</p>
</center>
</body>
</html>