#2041: Frontiers

[In a single framed picture a hand drawn rhombiod is shown. At the inside a few small arrows pointing to the four sides. The text in the middle reads:]

Human achievement so far

[Text above the top left side:]

Space

[Text above the top right side:]

The oceans

[Text below the bottom left side:]

The human mind

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Alaska

[Caption below the frame:]

Final remaining “frontiers,” according to popular usage