<Tr> <Th> Total length </Th> <Td> 801 ft (244 m) </Td> </Tr> <Tr> <Th> Height </Th> <Td> 213 ft (65 m) </Td> </Tr> <Tr> <Th> Longest span </Th> <Td> 270 ft (82.3 m) </Td> </Tr> <Tr> <Th> Clearance below </Th> <Td> 28 ft (8.6 m) (closed) 139 ft (42.5 m) (open) (mean high water spring tide) </Td> </Tr>

When was the last time tower bridge opened