הלכה אויף דניאל 6:10

Place where the worshiper prays. He should stand in a low place and turn his face to the wall. Windows or doors towards Jerusalem should be opened, and he should stand facing them when he prays, as it is said, "Now his windows were open in his upper chamber towards Jerusalem" (Daniel 6:11). There should be one fixed place set apart for prayer. It should not be recited in a ruin nor at the rear of a synagogue, unless the worshiper turns his face towards the synagogue. It is forbidden to remain seated at the side of one who is standing in prayer, or pass in front of him unless he has moved away from the worshiper to a distance of four cubits.