Alert is the northernmost city in Canada (the world?). Is Alert an
actual city where people live, or is it just a place where scientists
study the weather and army people go?

Alert in Nunavut claims to be the northernmost permanent settlement in
the world. It has weather and atmosphere testing stations, and a
Canadian forces presence. There have been people living there since
the 1950s, with a recent population of 75, but there appear to be no
Inuit residents. Alert is clearly not a city in the sense that we
usually use that word in the western world; and one wonders whether
there is anyone living there for whom it is really their home. Perhaps
you really need to go there to find out! (Main source -
http://encyclopedia.fablis.com/index.php/Alert,_Nunavut )