Translation of helmet in Spanish

I guess you know Spanish very well. I'm not on line most of the time. I think to get accommodation in the city is hard. I have many friends in Madrid, they all live outside the city. I think we can help each other to practice German or Spanish.
After ten minutes and after drinking a bottle of water we returned to our place. It was already three in the morning. We were unhappy to miss a great party, but our physical conditions were bad.
The biggest city in Germany is Berlin. The other big cities are not as big but some of them are really nice. And especially the smaller cities here are very charming and worth visiting.