What one may and may not pray facing

It is narrated from Sayyiduna Anas (may Allah be pleased with him) that he said: "I was praying facing a grave when Sayyiduna Umar (may Allah be pleased with him) saw me in that state and began calling out: 'The grave! The grave!' I could not understand what he meant, so I raised my head towards the sky (thinking that perhaps he was pointing to the moon or a cloud). Then he explained: 'The grave is right in front of you (that is, do not pray facing a grave).'" According to another chain, al-Hasan al-Basri (may Allah have mercy on him) also transmitted the like of this from Sayyiduna Umar (may Allah be pleased with him) through Sayyiduna Anas (may Allah be pleased with him).
This report is sahih (authentic); Imam al-Bukhari (may Allah have mercy on him) mentioned it in his Sahih in mu'allaq form (without a chain).

It is narrated from Sayyiduna Anas (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "A dog, a donkey and a woman (by passing in front of the one praying) interrupt the prayer."
[Takhrij and grading: Imam al-Harith bin Abi Usamah narrated it in his Musnad (Bughyat al-Bahith: 340). There is criticism of its chain because it is narrated only by the narrator Abd al-Hakam bin Abdullah al-Qasmali al-Ghafiqi; however, the basis of this hadith is narrated from various Companions in other books of hadith, including Sahih al-Bukhari and Sahih Muslim, which supports its text.]

It is narrated from Ibrahim bin Abd al-Rahman bin Awf (may Allah have mercy on him) that he said: "I was praying when a man began to pass in front of me, so I stopped him (from going ahead). Then I asked Sayyiduna Uthman bin Affan (may Allah be pleased with him) about the matter, and he said: 'O my nephew! This does not harm you (that is, it causes no defect in the validity of your prayer).'"
The chain of this report is sahih (authentic). Imam Ibn Abi Shaybah narrated it in 'al-Musannaf' (2809), and Imam Musaddad bin Musarhad in his 'Musnad'.

It is narrated from Muhammad bin Sirin (may Allah have mercy on him) that Sayyiduna Abu Sa'id al-Khudri (may Allah be pleased with him) was praying when al-Harith began to pass in front of him, or intended to pass, so he (in order to stop him) went so far as to intend to seize him by his hair. At this, al-Harith complained about it to Marwan. So Sayyiduna Abu Sa'id (may Allah be pleased with him) came to Marwan, and Marwan said (taunting): "If you people obey this man and his companions, they will surely make you Jews." Sayyiduna Abu Sa'id (may Allah be pleased with him) replied: "By Allah, you have lied! Even if you and your father were to become Jews, we would never follow in your footsteps and become Jews."
Ayyub (may Allah have mercy on him) said that Muhammad bin Sirin (may Allah have mercy on him) said: "He spoke the truth, for in the Days of Ignorance (Jahiliyyah), Judaism was presented to them (the Ansar), but they flatly refused to accept it."