Oddee has a collection of some truly amazing ice sculptures, the most impressive of which is this massive ice castle in China. The other sculptures are also fascinating though. It always amazes me how much artistry is required to make one of these pieces when it will only melt away eventually anyway.
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Seriously now: when I lived in Mayville, NY, I visited an ice castle they build in Chautauqua lake every year, and I already found that to be amazing. Some of these sculptures are extraordinary.