"Indeed he (Muḥammad pbuh) did see of the Greatest Signs of his Lord (Allah)." (V.53:18) Sahih al-Bukhari 4858

Arabic hadith text
حَدَّثَنَا قَبِيصَةُ، حَدَّثَنَا سُفْيَانُ، عَنِ الأَعْمَشِ، عَنْ إِبْرَاهِيمَ، عَنْ عَلْقَمَةَ، عَنْ عَبْدِ اللَّهِ ـ رضى الله عنه – ‏‏{‏لَقَدْ رَأَى مِنْ آيَاتِ رَبِّهِ الْكُبْرَى‏}‏ قَالَرَأَى رَفْرَفًا أَخْضَرَ قَدْ سَدَّ الأُفُقَ‏.‏
Translation
Narrated `Abdullah

(regarding the revelation) Truly he (Muhammad) did see of the signs of his Lord; the Greatest!' (53.18) The Prophet (ﷺ) saw a green screen covering the horizon.