1. Our flat is right beside a supermarket.
2. Does she speak any other languages besides
Spanish and Catalan?
3. There are many huge skyscrapers in New York
City besides the Empire State Building.
4. Help yourself to a drink and come and sit beside
me here on the sofa.

Besides = además (also, another reason, as well)
Beside = junto a, al lado de (near, at the side of)