<Tr> <Th> By topic </Th> </Tr> <Tr> <Td> <Ul> <Li> Diplomacy </Li> <Li> <Ul> <Li> Engagements </Li> <Li> Operations </Li> </Ul> </Li> <Li> Battle of Europe air operations </Li> <Li> Eastern Front </Li> <Li> Manhattan Project </Li> <Li> United Kingdom home front </Li> </Ul> </Td> </Tr> <Ul> <Li> Diplomacy </Li> <Li> <Ul> <Li> Engagements </Li> <Li> Operations </Li> </Ul> </Li> <Li> Battle of Europe air operations </Li> <Li> Eastern Front </Li> <Li> Manhattan Project </Li> <Li> United Kingdom home front </Li> </Ul> <Li> <Ul> <Li> Engagements </Li> <Li> Operations </Li> </Ul> </Li>

What was the cause of the second world war