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My 9 year old son and I have British passports, and my husband Spanish. We have a 19 hour layover in Miami when flying from Madrid to Colombia, and intend to leave the airport and stay overnight in a hotel preferably just with our hand baggage. First question: do we need any kind of visa before we fly, and indeed are we allowed out of the airport (sure hope so...!). Second, will luggage be checked all the way through to Colombia or will we need to recheck? (Flying with American Airlines). We hope to do a quick trip to South Beach to check it out! Thanks!