<Tr> <Td_colspan="2"> Part of Cold War and invasion of Czechoslovakia </Td> </Tr> <Tr> <Td_colspan="2"> Czechoslovaks carry their national flag past a burning Soviet tank in Prague . </Td> </Tr> <Tr> <Th> Date </Th> <Td> 5 January 1968--21 August 1968 </Td> </Tr> <Tr> <Th> Location </Th> <Td> Czechoslovakia </Td> </Tr>

Why was there a revolution in czechoslovakia in 1968