لَا إِلَٰهَ إِلَّا اللَّهُ الْعَظِيمُ الْحَلِيمُ، لَا إِلَٰهَ إِلَّا اللَّهُ رَبُّ الْعَرْشِ الْعَظِيمِ، لَا إِلَٰهَ إِلَّا اللَّهُ رَبُّ السَّمَاوَاتِ وَرَبُّ الْأَرْضِ وَرَبُّ الْعَرْشِ الْكَرِيمِ
La ilaha illallahul-'Adhimul-Halim, la ilaha illallahu Rabbul-'Arshil-'Adhim, la ilaha illallahu Rabbus-samawati wa Rabbul-ardi wa Rabbul-'Arshil-Karim
There is no deity but Allah, the Mighty, the Forbearing. There is no deity but Allah, Lord of the Magnificent Throne. There is no deity but Allah, Lord of the heavens and Lord of the earth and Lord of the Noble Throne.
Recite when in difficulty or distress during travel
The Prophet (PBUH) would say this dua in times of difficulty.