My family owns some land a few miles north of mount evans. it was 6:30 pm, dark, and i was observing the sky. it is very clear at this location so i watched some satellites and planes pass by. i looked to the southwest and saw 3 what i thought were satellites coming up above the tree line which i thought was interesting. they were in a straight line at a distance of 2 fingers wide at arms length in the sky. it wasn't long until i realized they just kept coming. one behind the other, coming into sight at tree line, and disappearing at about 60 degrees above horizon. they were at 240 degrees sw of my location. i witnessed at least 40 of these things in the span of about 10 minutes, and it was like nothing i have seen before.