Camping on Fraser/Moreton/Stradbroke islands - learning about local Aboriginal cultural heritage, species identification and respecting/looking after the natural environment, tidal movement and phases of the moon, beach erosion, as well as dingo safety.
Mossman Gorge and Cape Tribulation - this was after he'd been learning about rainforests in school so it was amazing to him to actually get out and walk in them and see the different layers of plants and look/listen for animals, etc. We also visited the crater lakes on the Atherton Tablelands and talked about how they were formed (volcanic vents).
We are intending to take him out to Carnarvon Gorge to camp when DS is a little bigger and there he will learn about the Aboriginal cultural history of the place (there is rock art and certain parts are sacred women's sites) as well as seeing an abundance of wildlife that he wouldn't see in and around Brisbane. Not to mention the geology of the area. The gorge is essentially massive sandstone cliffs and inside the gorge is positively lush compared to the surrounding plains. Formed by gradual erosion from Carnarvon Creek over millions of years. I won't go on - I'm starting to sound a bit science nerdy...
With the natural environment, I definitely have an advantage having worked with the QPWS folk for several years, and DH and I have always been interested as we love outdoor activities.
Often you find fantastic tours that are a wealth of information and geared towards kids. When we go camping somewhere new I always print out maps and national park information for SS to read through so he gets a sense of what's significant about the place/s we're going and knows what to look out for when we're bushwalking, etc. It also helps him get excited about it in the lead up as he was not always the most avid camper .
We haven't taken him overseas (can't afford it) but from our previous travels I can easily say learning about art, culture, history, geography.