Помогите переделать вопросы в пассивный залог (passive voice).

1) When... (the eiffel tower build )?
2) What.. (the Taj Mahal/make) of?
3) Why ... (the Egyptian Pyramids/build)?
4) Which famous monument ... (can/see) from almost every part of the city?
5) iT.. (estimate) that 2 to 3 million people died while building a monument. Which one?
6) Which of these famous sites ... (endanger) by tourism?
7) According to legend, which famous building ... (destroy) if the ravens ever leave it?

1) When was the Eiffel tower built? 2) What is the Taj Mahal made of? 3) Why were the Egyptian Pyramids built? 4) Which famous monument can be seen from almost every part of the city? 5) It is estimated that 2 to 3 million people died while building a monument. Which one? 6) Which of these famous sites is endangered by tourism? 7) According to legend, which famous building will be destroyed if the ravens ever leave it?

1. When was the Eiffel Tower built?2. What is the Taj Mahal made of?3. Why were the Egyptiam Pyramids built?4. Which famous monument can be seen from almost every part of the city?5. It is estimated that 2 to 3 million people died while building a monument. Which one?6. Which of these famous sites endangered by tourism?7. According to legend, which famous building will be destroyed if the ravens ever leave it?