Translation of arduous in German

Sorry, I don't know but I have asked some friends for help. Hope they will answer soon! Where did you find this sentence? He's originally from Scotland, so I hope you can understand his accent.
We decided to walk back and explore the city on foot. It was hard to cross the streets as there was an endless flow of motorcycles and bikes. One needed to just enter the street and cross it.
The next morning we got up at 4.30. At sunrise, one hour later, a taxi waited for us in front of the hotel. He would take us on a 2 hours private sightseeing tour around Arequipa, just before traffic started.