Thinking about big-scale crater gardens, I guess one of the world's biggest crater "gardens" must be The Eden Project in the UK.
The Eden Project - Wikipedia
The Eden Project
This popular visitor attraction was built between 1998 and 2001 to celebrate the Millennium. It's situated a few miles from St Austell in Cornwall and is built in a disused clay quarry. The Eden Project exists to teach people about plant life in all it's incredible variety. For those of you that don't know the UK, Cornwall is in the south-west and is already one of the warmest places in the country. At the bottom of the giant pit it's even warmer. There are then giant greenhouses at the lowest point called biomes - to give you some idea of scale, the tropical greenhouse covers nearly 1.58 hectares (3.9 acres) and stands 55m (180ft) at it's highest point. The combination of the protected environment of the pit plus the greenhouses means they can grow tropical plants such as coffee and fruiting bananas.
http://en.m.wikipedia.org/wiki/File:Eden_Project_geodesic_domes_panorama.jpg
http://en.m.wikipedia.org/wiki/File:Eden_project_tropical_biome.jpg
The range of climates they have created is impressive from Cornwall's own sunny temperate to Mediterranean to tropical. All the areas outside the biome greenhouses are planted to with a mixture of edibles and ornamentals. You can spend the whole day with ease and it's still popular with plant lovers and holiday makers.
I'm a gardener who's also interested in architecture and I love it there. This thread has made me think: There must be a whole lot of former quarries out there just waiting to be "cratered"! Thanks for the inspiration.
