Nice 50 meter fountain. Looks a bit like a rustic version of Geneva. Its on Lake Nyos in Cameroon. But this fountain is driven not by pumps, but by dissolved carbon dioxide. Its meant to prevent a repeat of the 1986 limnic eruption that killed 1,800. Netorama has the whole story here. As well, Wikipedia articles on Lake Nyos, limnic eruptions, and most interestingly, the site of the organization that constructed the fountain.
While the fountain above should keep Lake Nyos safe as long as nothing else bad happens (like the collapse of the natural dam that creates the lake), nobody has yet done anything about the potentially much more dangerous Lake Kivu.
