Sinkholes

3. an empty space or opening in the middle of something or between two things
8. to remove dirt from something by rubbing it hard with something rough
9. a large hole or empty space
11. the hard area of rock in the ground that holds up the loose soil above
13. the process of rubbing away the surface of something
15. in a way that does not show careful choice or planning, usually with harmful results
17. to ask yourself questions or express a wish to know about something
18. to cover an area of ground with a hard, flat surface of pieces of stone, concrete, or bricks
19. able to be dissolved when mixed with a liquid
21. a salt containing carbon and oxygen together with another chemical
22. to be absorbed by a liquid, especially when mixed, or (of a liquid) to absorb a solid
23. a central part of something from which other parts can develop or grow, or which forms a support
24. sand or soil that is carried along by flowing water and then dropped, especially at a bend in a river or at a river's opening
25. something that blocks a road, passage, entrance, etc.
26. water that collects below the surface of the earth

1. the fact of someone or something not succeeding
2. a mass of rock and earth moving suddenly and quickly down a steep slope
4. a typical quality or an important part of something
5. to limit an activity, person, or problem in some way
6. to cause food, drink, pills, etc. to move from your mouth into your stomach by using the muscles of your throat
7. thick, heavy soil that is soft when wet, and hard when dry or baked, used for making bricks and containers
8. a hole in the ground, especially in an area of limestone rock, that has been formed naturally, for example by water that has worn away the rock
10. the system of water or waste liquids flowing away from somewhere into the ground or down pipes
12. a tube inside which liquid or gas flows from one place to another
14. very ordinary and therefore not interesting
16. not in the intended way
19. the material on the surface of the ground in which plants grow
20. a white or light grey rock that is used as a building material and in the making of cement