<Table> <Tr> <Td> </Td> <Td> This article needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (January 2012) (Learn how and when to remove this template message) </Td> </Tr> </Table> <Tr> <Td> </Td> <Td> This article needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (January 2012) (Learn how and when to remove this template message) </Td> </Tr> <P> A sally port is a secure, controlled entryway to a fortification or prison . The entrance is usually protected by some means, such as a fixed wall on the outside, parallel to the door--which must be circumvented to enter and prevents direct enemy fire from a distance . It may include two sets of doors that can be barred independently to further delay enemy penetration . </P> <P> From around 1600 to 1900, a sally port was a sort of dock where boats picked up or dropped off ship crews from vessels anchored offshore . That meaning occasionally still occurs, especially in coastal Great Britain . </P>

What is a sally port in a prison