A Google Earth tile (URL from Google Maps' observed behavior)
<p>

http://kh0.google.com/kh?n=404&v=20&t=tqtrtstqttssq
<p>

<img src="http://kh0.google.com/kh?n=404&v=20&t=tqtrtstqtts">

<p>
The next higher zoom level of this image:

<p>
<table>
<tr>
<td> <img src="http://kh0.google.com/kh?n=404&v=20&t=tqtrtstqttsq">
<br>tqtrtstqtts<b>q</b>
<td> <img src="http://kh0.google.com/kh?n=404&v=20&t=tqtrtstqttsr">
<br>tqtrtstqtts<b>r</b>
<tr>
<td> <img src="http://kh0.google.com/kh?n=404&v=20&t=tqtrtstqttst">
<br>tqtrtstqtts<b>t</b>
<td> <img src="http://kh0.google.com/kh?n=404&v=20&t=tqtrtstqttss">
<br>tqtrtstqtts<b>s</b>
</table>

(It is a picture of Roseburg, Oregon, USA.)

<p>

The initial T means "the whole Earth". Changing the second T to S gives a 404 page, because that moves the picture from Oregon to someplace on this part of the earth:
<p>
<img src="http://kh0.google.com/kh?n=404&v=20&t=ts">
<br>ts
<p>
That is a part of the earth with a very small amount of imagery available, which made it almost a certainty that I would hit a missing image by editing the URL like this.

<p>
We can find the best image possible by removing letters until we stop getting a 404 error:

<p>
<img src="http://kh0.google.com/kh?n=404&v=20&t=tstrtst">
<br>tstrtst

<p>
Looks like "tstrtst" is in Antarctica!