You, too, can be a space alien! All you'll need are a stick, some sun, string, and a way of making marks. At the end of this, you'll be able to perform feats that have caused many over the decades to say that the ancient Egyptians and others 'must' have been visited by space aliens.
What you'll do is construct a very accurate definition for north+south. From there, you can build your own pyramid aligned accurately to north/south. Technologies involved are all 6000+ years old.
So, first step is to get a long, straight stick. You can verify that it's straight by checking against the string in your which way is up apparatus. (Notice that it, too, only uses 6000+ year old technology.)
Next, put the stick in to an area of flat ground. It's best if you plant it straight up and down. You can use your terribly advanced up-down apparatus for guidance on which way is up.
Now for the hard part. Tie the string around the stick and your marker. Pull the string taut and mark a circle around your stick. Retie the string to marker and shorten or lengthen the distance from stick, to make another circle. Repeat a few times so that you have a variety of circle sizes.
Back to easy. A little patience is required. Each time the sun's shadow from your stick hits one of the circles, mark the location. If you're in a cloudy place, you really want a bunch of circles. What we're looking for is the shadow to hit the same circle twice -- once earlier in the day and once later.
Next to last: after you have a nice pair of marks on one of your circles, find the mid-point between the pair.
Finally: Draw a straight line from your stick to this mid-point mark. This line is the north-south line for your location.
There are some elaborations you can do here, for accuracy and for large scale construction. But you're now done with the basics. And can construct your own objects aligned accurately to north-south, just like the 'space aliens'. Well, more seriously, just like our ancestors from several thousand years ago.
You can find the midpoint between your marks by eye pretty well. You'll be most accurate if the distance between marks isn't very large. This means you'll want a circle that's not much larger than the shortest shadow of the day. So for accuracy, you'll want to try 2 days. On the first day, do the procedure above, but also mark the shortest shadow. On the second day, draw a new set of circles, starting with one a bit larger than this and then getting larger.
You find the midpoint even more accurately by straight edge and compass angle bisection. Name sounds imposing, but the application is simple enough that even clumsy me was doing it by age 10.
If it's summer, and especially if you live at low latitudes, the shortest shadow can be very short. That makes it hard to have a long baseline for your north-south line. After you've marked north-south, one way to make it as long as you'd like is to take a long roll of string and tie it to your stick. Then walk it far from your stick and have a friend move you left and right until the string passes straight over your mark.
You can also compare your north-south line to magnetic north. For almost all the world, magnetic north isn't the same as geographic north. (Plus, magnetic north moves year by year.) The difference between your line and magnetic north should be about the same as the magnetic declination calculated at
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