Other Achievements of Early People

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Across
  1. 3. by the sea; sandy and a very popular mark
  2. 4. a system in which people can send messages
  3. 6. a stop; usually in travelling
  4. 8. A river in Egypt
  5. 11. people who explore
  6. 12. people who sell items
  7. 13. singular for "clothes"
Down
  1. 1. Started a monetary system
  2. 2. a sort of bridge; waterway
  3. 4. Highly skilled sailors and ship-builders
  4. 5. moved with care
  5. 7. A state of matter
  6. 9. costing a lot of money/currency
  7. 10. A country with mountains