From the nature of the universe (that's if there is only one) to the purpose of dreams, there are lots of things we still don't know – but we might do soon:
1 What is the universe made of?
2 How and where did life begin?
3 Are we alone in the universe?
4 What makes us human?
5 What defines consciousness?
6 Why do we dream?
7 Why is there stuff?
8 Are there other universes?
9 Where do we put all the carbon?
10 How do we get more energy from the sun?
11 What's so weird about prime numbers?
12 How do we beat bacteria?
13 Can computers keep getting faster?
14 Will we ever cure cancer?
15 How will robots advance?
16 What's at the bottom of the ocean?
17 What's at the bottom of a black hole?
18 Can we live forever?
19 How do we solve the population problem?
20 What is time?