As an example of what can be achieved by human beings working together, you would be hard pressed to find better than the International Space Station, or the I.S.S. as it's more commonly known. The building of the station, which commenced in 1998, has involved contributions from the American, Russian, European, Canadian and Japanese space agencies.
Housing astronauts all year round, having been the temporary home of over two hundred of them so far, and orbiting the Earth once every 90 minutes, the International Space Station has thus far cost a grand total of $157 billion. That cost will continue to rise as further improvements are made to the station, with fresh facilities and features added. Astronauts on the station experience growth of over two inches during their stay - an effect of living in a zero-gravity environment!