add a box on a archive sidebar

Hi,

for my site i need to add a "promotion box" only on a certain archive sidebar
for examples i need the "promotion box" to show on:
http://www.mysite.com/archive/world/
but not on:
http://www.mysite.com/archive/politics/

Since the template "category" is unique, how can I show the "promotion box" only on a certain archive page?

Thanks