SQL: Retrieving data from two tables via a 3rd linking key table

If anyone could help with an SQL query I would be most grateful, thank you in advance.

I have 3 tables as follows:

families (id_family, family)

levels (id_level, level)

level_families (id_level, id_family)

I'm trying to retrieve all levels with their families concatenated, I know I need a join but my SQL is rusty and I can't get my head around this one.

Thanks again for any help,

Paul