At the 39th parallel
after the 38 but before the 40th
hey, just between the 38th and the 40th.....
Beware the 39th step. Note that 39 is 13 multiplied by 3. Both of these are bad numbers, so 39 is the ultimate bad number. If you're ever on a staircase that high, count your steps and skip over the 39th.