Why does this pick all of my `<li>` elements in my document?

```
HtmlWeb web = new HtmlWeb();
HtmlDocument doc = web.Load(url);

var travelList = new List<Page>();
var liOfTravels = doc.DocumentNode.SelectSingleNode("//div[@id='myTrips']")
                     .SelectNodes("//li");

```

What I want is to get all `<li>` elements in the `<div>` with an `id` of "myTrips".