From Wikipedia we learn that "Iron Sky" is [...] a dark science fiction comedy that plays with Finland's history of being oppressed by Sweden and Russia, Iron Sky is a deliberate thematic throwback, a modern implementation of once-popular science fiction tropes that have fallen into disuse, such as Nazis in space.
In addition, from the summary we know that [...] as World War II comes to an end in 1945, Hans Kammler and other German scientists make a breakthrough in anti-gravity research. From a secret base in the Antarctic, Nazi spaceships are sent to the "dark side" of the Moon to establish the military base "Schwarze Sonne" (Black Sun). Their plan is to build a powerful fleet and return to conquer Earth. The film is set in the year 2018 when their descendants finally return.
Here are the 2 teasers:
Pretty cool n'est-ce pas?