Hard clean riddles with simple answers

Where can you find rivers with no water, cities with no buildings and forests with no trees?

What has one head, one foot and four legs?

When you put this in a heavy wooden box, the box will become lighter.

A group of campers have been on vacation so long, that they've forgotten the day of the week. The following conversation ensues. Darryl: "What's the day? I dont think it is Thursday, Friday or Saturday." Tracy: "Well that doesn't narrow it down much. Yesterday was Sunday." Melissa: "Yesterday wasn't Sunday, tomorrow is Sunday." Ben: "The day after tomorrow is Saturday." Adrienne: "The day before yesterday was Thursday." Susie: "Tomorrow is Saturday." David: "I know that the day after tomorrow is not Friday." If only one person's statement is true, what day of the week is it?

Thousands lay up gold within this house, but no man made it. Spears past counting guard this house, but no man wards it.

I speak without a mouth and hear without ears. I have no body, but I come alive with wind. What am I?

You write on me and secrets I can keep. In places never seen. I spin like a top. Though stiff as a board, I'm often described like a mop. What am I?