This is my first map mod, so please don't judge it in an unkind way. This mod brings a tunnel connecting the interior of St. Mark’s Bistro and the streets of Liberty City. With this mod, you can go into and go out of St. Mark's Bistro easily. Beside that, this mod also filled a crevice on the exterior wall of St. Mark’s Bistro, and fixed the glitch that the camera shaking when you climb the stairs outside the bistro.
Notice: The game save file in the package you downloaded is NOT a part of this mod, which just provide a convenient way to the liberty city. If you have a better way to get to the hidden city, just ignore the save file.
The levelmap.ide file in the package is NOT a part of this mod, too. It from the mod "Liberty City Solid terrain v2.0", created by alexandrovich. But using his mod along with my mod, you could hang around the streets of Liberty City at liberty!
Installation Tutorial: simply replace those files in the gta3.img archive with the files with the same name in "gta3.img" folder. And optionally, you may extract levelmap.ide file to your GTA San Andreas data maps leveldes folder.