Setting channel url format to include value of entries fieldtype URL

Question

I have a channel with an entry type which has a simple dropdown for {region} and an entries fieldtype which links to a channel of destinations.

I'd like the URL format for the channel to be /region/destination/slug. If I do /{region}/{destination.url}/{slug} the output is /region-name//entry-slug, i.e. nothing is output for the destination.

What should I have where I currently have {destination.url}?

Answer 1

It needs to be:

{destination.first().slug}

Or if this is for Craft 3:

{destination.one().slug}