CSS problem - learning experience

[Daudio]

I have a little problem in one of my web pages, and while I could fix it easily with a workaround, I thought it might be a good chance to learn something about CSS positioning.

In the page http://daveayers.com/Modeling/RRCranes.htm, the third H2 is appended to the right of the previous block, rather then exhibiting its own block behavior and sitting below it. I could insert a 'clearboth' before it and achieve the desired results, but I want to understand what is going wrong here and learn to prevent these kind of problems rather then patching them.

The code before and after the non-block like behavior is:

	<div class="thumbnail">
<a href="images/MOW_Equip.jpg"><img border="2" src="images/MOW_Equip_small.jpg" alt="MOW Equip. models" width="200" height="55"></a>
     <br> A small track crane made from some Selly parts and more, a brass Burro crane, among some of my MOW equipment
	</div>

<p>&nbsp;</p>  ***problem around here***

<h2>'G' Gauge Freelance Railroad Crane:</h2>

The CSS for the '.thumbnail' div that preceeds the wonky acting H2 is:

.thumbnail
{
	float: left;
	width: 210px;
	border: 1px solid #999;
	margin: 10px;
	padding: 5px;
	background-color: transparent;
}

This is an older page that I added some new content to. The old way was to use a Table to layout the images, but now I am using the 'thumbnal' divs. to let them float to any size screen. Not a perfect solution with differently sized images, but I kinda like it.

I hope someone can help me understand what is going on here, and that will help me get a better internal model of CSS. I am still trying for that 'Ah Ha' moment...

[Kelvyn]

Clearing floats can often be a problem. After a very quick look, try putting <br clear="all" /> after the last thumbnail div.

[Daudio]

Kelvyn,

Clearing floats can often be a problem. After a very quick look, try putting <br clear="all" />

There are a number of ways I can add a 'clear all', but that is the workaround I refered to. I was hoping that understanding what underlies the clearing floats problem would lead to more insight into CSS