So my wife and I will have a 15 hr layover at ICN in March.

We are flying in OZ from Sydney to ICN then onto JFK. We land in ICN around 7pm and dont leave till the next morning at 10am.

What can we do in that time to get the most out of it? I doubt we will need much sleep.

Also I dont know how luggage will be handled. Do we have to get it or will it just sit there overnight?