Unbendium

Unbendium is a metal element, rare and hard to find in the multiverse. Though it is very valuable, not because of it's rarity, but instead because, as it's name implies, items cast from unbendium simply do not bend. This makes it ideal for armor plating and the internal supports of ships and buildings. However, because of it's rarity, most ships and buildings do not have this metal support. Many wars have been fought over access to supplies of unbendium ore. Ironically, these wars have driven up the demand for unbendium itself, which further fuels the land-wars.