Getting around the city, and especially downtown Manhattan, could be difficult this weekend because of the anniversary of 9/11 and the security surrounding the ceremony.

Here's what you need to know:

• Beginning Saturday at midnight, northbound West Street between Battery Place and Murray Street will be closed.
• On Sunday starting at 8 a.m., West Street going south between Murray Street and Battery Place will be shut down.
• On Sunday, from early in the morning until 6 p.m., all streets from Battery Place to Vesey Street will be closed.  There will be bus detours on the M-5, M-20, M-22, X-1 and X-10.
• The MTA will close the subway staircases on Church Street, Park Place and Barclay and Vesey streets.
• Subway trains will bypass the Cortlandt Street station on the R line for four hours Sunday morning, between 7 a.m. and 11 a.m.
• Subway entrances on Church Street at Chambers, Warren and Murray streets will remain open.  The subway station at Park Place and Broadway, near City Hall, will also be open.
• PATH service will be suspended between EXPL and WTC from 7 a.m. and 11 a.m.