BBC | 20 September 2010 | Last updated at 10:34 GMT (click above for link)
1. What is the meaning of life?
2. Is there a God?
3. Do blondes have more fun?
4. What is the best diet?
5. Is there anybody out there?
6. Who is the most famous person in the world?
7. What is love?
8. What is the secret to happiness?
9. Did Tony Soprano die?
10. How long will I live?
20 September 2010 Last updated at 10:34 GMT
Top 10 'unanswerable' questions revealed
"What is the meaning of life?", "Is there a God?" and even "Do blondes have more fun?" - these are apparently the world's trickiest questions.
Internet search engine Ask Jeeves has compiled what it called a top 10 of "unanswerables" in the past decade.
The list is based on some 1.1 billion queries made on the site since its launch in 2000.
Other weighty issues include mortality, love and fame, but "did Tony Soprano die?" also made it on the list.
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Ask Jeeves said that this was because many users of the site had been inquiring about what happened to the TV gangster after the final episode of the popular US drama The Sopranos.
The site also said it was launching an "unanswerables" page to help people shed light on some of the most tricky questions.
Since its launch Ask Jeeves - with its trademark butler - has been struggling against more popular search engines, such as Google.
The original idea behind Ask Jeeves (known as Ask outside the UK) was to allow users to get answers to their questions, as well as traditional keyword searching.