What causes blood in your urine?

Infection, tumor,etc: Most common cause is a bladder infection, usually associated with symtoms of urinary frequency, buring on urination, foul smelling urine & ?Pain. Can be a sign of cancerin urinary tract anywhere from kidney -> bladder, prostate or urethra, kidney disease such as glomerulonephritis, kidney stone, blood vessel abnormality, or medications. Microscopic blood from all of above + interstuitial cystitis.