<Tr> <Td> Capital </Td> <Td> Berlin </Td> <Td> Tokyo </Td> </Tr> <Tr> <Td> Largest city </Td> <Td> Berlin--3,513,026 (6,000,000 Metro) </Td> <Td> Tokyo--13,185,502 (35,682,460 Metro) </Td> </Tr> <Tr> <Td> Government </Td> <Td> Federal parliamentary constitutional republic </Td> <Td> Unitary parliamentary constitutional monarchy </Td> </Tr> <Tr> <Td> Official languages </Td> <Td> German (de facto and de jure) </Td> <Td> Japanese (de facto) </Td> </Tr>

What event officially formed the alliance between italy and germany in wwii