Why can I not establish a Trade Route?

[Optimistic Cynic]

I just started a new Civ V game, after playing a few Beyond Earth games, and I've come across something odd.
I have two cities. The second city is seven tiles away from the first. The bar shows that I have 0/2 trade routes utilized. I have a caravansary built in both cities. But when I attempt to build a caravan, it states that I cannot build the unit because I have no available trade routes (it says the same for sea routes). I built the Petra and got a caravan, but it somehow cannot reach my second city. Did somethng change recently?

[Random Reference #98]

You need a grannary in a city to be able to trade food to another and workshop to trade production.

[kafkaclone]

you also need to be close enough to the civ or city state you are trading with to establish the route. certain civs have a farther trading range. also building a caravanassary will increase the range. building cities closer to the civs or city states you want to trade with and then building the caravan in that city will allow you to trade with them if you are sufficiently close.

[Aliapoh]

You need to have workers to establish trade routes silly!

[SamBC]

Originally posted by Oswald for the win- Oswin!:

You need to have workers to establish trade routes silly!

No, you don't.

[jeremygauden]

Originally posted by Random Reference #98:

You need a grannary in a city to be able to trade food to another and workshop to trade production.

Yupp yupp

[Optimistic Cynic]

Awesome, thanks! Recent change, eh? oh well, it will slow down the beginning of the game a bit but I'll deal with it. :)