<Tr> <Th> Main venue </Th> <Td> Khalifa International Stadium </Td> </Tr> <Tr> <Td_colspan="2"> <Table> <Tr> <Th> <London 2017 </Th> <Th> Eugene 2021> </Th> </Tr> </Table> </Td> </Tr> <Table> <Tr> <Th> <London 2017 </Th> <Th> Eugene 2021> </Th> </Tr> </Table> <Tr> <Th> <London 2017 </Th> <Th> Eugene 2021> </Th> </Tr>

Where will the next world athletics championships be held