Well, i'm portuguese, so...
...
*cricket sound*
Seriously though, apart from stuff associated with maritime discoveries (which most of my countrymen pathetically still hold onto pridefully, despite having been centuries ago), like the contributions of 16th century mathematician and cosmographer Pedro Nunes to maritime navigation, among some other nautical techniques, tools and ships, there's not much to talk of.
All other achievements are, for some strange reason, healthcare-related. There are a few, but since they're mostly achievements and discoveries, and not inventions per se, i'll just cite Egas Moniz, our Medicine Nobel Prize winner, for the Cerebral Angiography and the Prefrontal Leucotomy (aka Lobotomy), for the treatment of certain psychosis.
Ok, yeah, having invented the lobotomy is kinda cool, but it's also a bit lame, since it was always controversial, and was soon replaced with less damaging approaches. But i guess it will have to do.
So yeah, lobotomy
