Changing Nature: An Hourglass

I've always wanted to build a LEGO hourglass, and this contest is the perfect opportunity to do that! This hourglass display is approximately 10 inches tall (~26cm), and has a mini-scene in the top and bottom bulbs.

You can decide for yourself whether to interpret the top bulb to reference mankind and its growing dominance over nature (the bottom bulb), or for the display to refer to the growing threat of deforestation and pollution to nature, or both bulbs as a metaphor for something totally different. That's part of what art is.

The entire build is 520 pieces, with the hourglass itself being 298 pieces, and each mini-scene being about 111 pieces each. Please comment to tell me how you interpret the display, or to tell me what to think of the build.