In which direction should one pray if one does not know?

From Zurarah bin Muslim, from Abu Jafar (a.s.), who said:“It is enough for the person who is constantly confused to turn in any direction if he did not know where the direction of prayer is.” From Mu’awiyah ibn Ammar that he asked him about someone who is in prayer. Then, when he has finished, he looks and sees that he has strayed off to the right or left of the direction of prayer. He (a.s.) replied: His prayer is already finished. What is between East and West is the direction of prayer, and this verse was revealed to him who is confused about the direction of prayer: {God is in the East and the West. Wherever you turn, there is the face of God. God embraces and knows everything. (2:115)} [Man-La-Yahdhru Al-Faqih, Volume 1, Page 276]

عن زرارة ومحمد بن مسلم ، عن أبي جعفر عليه‌السلام أنه قال : « يجزي المتحير أبدا أينما توجّه إذا لم يعلم أين وجه القبلة » (٧). وفي الصحيح ، عن معاوية بن عمار : أنه سأله عن الرجل يقوم في الصلاة ، ثم ينظر بعد ما فرغ فيرى أنه قد انحرف عن القبلة يمينا أو شمالا فقال : « قد مضت صلاته ، فما بين المشرق والمغرب قبلة ، ونزلت هذه الآية في قبلة المتحير : ( وَلِلّهِ الْمَشْرِقُ وَالْمَغْرِبُ ، فَأَيْنَما تُوَلُّوا فَثَمَّ وَجْهُ اللهِ