"uss against the world" is great way to put it, and it's especially great to see the kids adopt that as they explore something new. Three brothers could be fighting, annoying, etc. right up to the point when they realize that there is safety in numbers. I still remember them exploring a square in Cartagena when the oldest one was 10 and the youngest 5. They would see something interesting little bit further away from us (parents) and would look at each other and decide whether to engage. They ended-up making new (temporary) friends, getting seeds to feed birds and more as they built their confidence while looking after each other.
For the coming summer I've promised to get the two oldest (now 18 and 15) plane tickets to Madrid, Interail (Eurorail) passes, and flight back to US from Helsinki 3 or 4 week later. They'll figure it out, have fun and hopefully don't do too much dumb stuff. Way to bond before the oldest one leaves to college. The middle one gets to do similar trip again in 3 years when he graduates with his younger brother; who in turn will have his trip one year later (hopefully his oldest brother will be available to join him so that everyone will end up with 2 trips with each of their brothers).
My kids have been to a lot of places, and have been questioned about the logic of taking a 4-year old to Machu Picchu or wherever as they won't remember it.
I've said that it doesn't matter if they remember it. It's much more important that they experience it.
You can only experience Rome as a four-year old when you are four years old, there is no chance of getting that experience ever again their lives. They can experience Rome again, and again as an adult if they want, but being 4, 8, 12 or teenager at new place is not something that anyone has a chance of ever repeating.
They remember somethings, forget others, but come away with an interest in people, places, environments, etc.
For the coming summer I've promised to get the two oldest (now 18 and 15) plane tickets to Madrid, Interail (Eurorail) passes, and flight back to US from Helsinki 3 or 4 week later. They'll figure it out, have fun and hopefully don't do too much dumb stuff. Way to bond before the oldest one leaves to college. The middle one gets to do similar trip again in 3 years when he graduates with his younger brother; who in turn will have his trip one year later (hopefully his oldest brother will be available to join him so that everyone will end up with 2 trips with each of their brothers).