The Caravanner's Wigwam is unlocked at level 34. After restoring the building you will be able to send caravans to distant towns and get rare goods. Tap the Caravanner’s Wigwam to open the caravan-sending interface.

 

Each town is rich with its own unique goods:

Your chances of getting different goods from the towns vary. However, you can add ingots to the caravan to boost your chances of receiving rare products and chests. ingots are twice as efficient when you use the Valuable ingots prediction at the Oracle's House.