Translation of suppose in Spanish

We bought a Sandwich and were looking for a taxi, but the streets were so crowded that we had to wait nearly one hour to find a cab. We even had to walk a few blocks in order to catch one.
I wish you would help me to improve my Spanish. I am studying law in Germany and I am trying to learn Spanish. I hope you can help me and I could help you to learn German. Have a great day.
We had never seen a similar landscape. The lagoons had different kind of colors, blue, white, green and red. They were all surrounded by rocky, dark volcanoes making the entire landscape surreal.