two layers of <a>

[jidanni@xxxxxxxxxxx]

Why the two layers of <a> even if it passes
$ validate http://en.wikipedia.org/wiki/Oaxtepec
*** Errors validating Oaxtepec: ***
Error at line 2, character 33:  there is no attribute "class"
Error at line 152, character 10:  end tag for "ul" which is not finished
Error at line 177, character 10:  end tag for "ul" which is not finished

Why the </a> halfway through the first pair of
   Coordinates: 18°54′N 98°58′W / 18.9°N 98.967°W / 18.9; -98.967

Why does it look fine in some browsers but ah-ha caught you in emacs-w3m?

Could it be that Firefox and Chromium are fooled into thinking that the
outer <a id...> which lasts through the whole six coordinates should
render as a clickable link... which it apparently does even with
stylesheets off. Only emacs-w3m renders it right, revealing the badly
written HTML!

Here's the code,
<p><span style="font-size: small;"><a id="coordinates"><a href="/wiki/Geographic_coordinate_system" title="Geographic coordinate system">Coordinates</a>: <span class="plainlinks nourlexpansion"><a rel="nofollow" class="external text" href="http://toolserver.org/~geohack/geohack.php?pagename=Oaxtepec&amp;params=18_54_N_98_58_W_region:MX_type:city_source:GNS-enwiki";><span class="geo-default"><span class="geo-dms" title="Maps, aerial photos, and other data for this location"><span class="latitude">18°54′N</a> <span class="longitude">98°58′W</span></span></span><span class="geo-multi-punct"> / </span><span class="geo-nondefault"><span class="geo-dec" title="Maps, aerial photos, and other data for this location">18.9°N 98.967°W</span><span style="display:none"> / <span class="geo">18.9; -98.967</span></span></span></a></span></span></span></p>