Nginx -- static file serving confusion with root & alias

I need to serve my app through my app server at `8080`, and my static files from a directory without touching the app server. # app server on port 8080 # nginx listens on port 8123 server { listen 8123; access_log off; location /static/ { # root /var/www/app/static/; alias /var/www/app/static/; autoindex off; } location / { proxy_pass http://127.0.0.1:8080; proxy_set_header Host $host; proxy_set_header X-Real-IP $remote_addr; proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; } } Now, with this config, everything is working fine. Note that the `root` directive is commented out. If I activate `root` and deactivate the `alias`, it stops working. However, when I remove the trailing `/static/` from `root`, it starts working again. Can someone explain what's going on?