Add the tags to create an unordered list in an ordered list.

<html>
<body>
<ol>
<li>Travel Destinations
<ul>
<li>Vienna</li>
<li>Bucharest</li>
<li>Bratislava</li>
</ul>
</li>
</ol>
</body>
</html>
]]>

Add the <ol> tag and the <ul> tag. Then close the lists with </ul> and </ol>.