Videos that show the claimed impact crater of the chemical strike in Khan Sheikhun, they should be in filming order.
Just to make sure that we are talking about the same thing(the image is from the second video):
https://s4.postimg.org/vz54vio4d/videoplayback2.mp4_snapshot_00.37_2017.04.06_19.png

>https://www.youtube.com/watch?v=MES_h5mGc8A
April 4th, at ~10, this is the first time the crater is shown and it looks like it's wet. There is a circular thing and two metal pieces inside the crater. The end of the big metal piece roughly points to SW direction. The big metal piece has a slight greenish colour at some places.

>https://www.youtube.com/watch?v=0bJw84eXALs
April 4th, around noon, the crater is dry, the big metal piece now has uniform grey colour, everything else looks the same, except I think the two white rocks at the NE side of the crater weren't there in the previous video.(maybe they were, but they aren't white when wet?)

>https://www.youtube.com/watch?v=yBB5zBKtC-k
April 4th , at ~14-15, no red sign, so it was filmed before the next video. There is only a quick glimpse of the crater, but the circular thing is missing, the small metal piece was moves, and a white something  - plastic bag? - appears in the crater.

>https://www.youtube.com/watch?v=uk6cqg6BaJU
Long video, the relevant part starts at 07:56. April 4th, at ~17, this is so far the first recorded sample collection attempt, from none other than the White Helmets! The red signs that appear in later videos originate from this team. Mostly soil samples are collected, but I can see a dead bird and something that looks like a metal piece as well. The small metal piece in the crater was moved, but it wasn't collected.

>https://www.youtube.com/watch?v=Qeosawyrgyo
April 5th, around noon, very professional sample collecting, first appearance of the reg sign, no white gloves, the big metal piece was moved(or bent, rather), it points to NE direction.

>https://www.youtube.com/watch?v=YGdOKGCpF5s
>https://www.youtube.com/watch?v=57LaZ1m49qQ
April 6th, around noon, no white gloves, the small metal piece was removed, but it's not clear who did it.

>https://www.youtube.com/watch?v=IyFAl2gjZJQ
April 6th, The imam in black also appears in the previous video, so I think it was shot just a bit later. There are 4 white gloves next to the crater, the 4 men from "Idlib Health Directorate" are wearing white gloves (and face masks), and the guy in the right is holding a pack of gloves at the very beginning of the video. An earlier state of the crater is shown at the end of the video.

>facebook--kareem.shaheen/posts/10154257460555583
April 6th, at ~13, several white gloves are left around the crater(but 0 in the crater)

>https://www.youtube.com/watch?v=vW_Jwq3vhCY
April 6th, at ~14-15, likely a bit before the drone footage in the next video, 2 gloves in the crater

>https://www.youtube.com/watch?v=0_1fkKEEJ5E
April 6th, around 16, many white gloves scattered around the crater. One white glove in the crater at 00:11, but two gloves at 00:15. The segment in the beginning was shot around one hour later than the drone part. When the camera zooms out at 00:38, 2 rather fresh craters can be seen in the green field, are they connected to the chemical attack?

>https://www.youtube.com/watch?v=tayK50Ggs9w
April 6th, late afternoon, just a bit later than the previous video, they finally collected the gloves!

>https://www.youtube.com/watch?v=hpvRwzUk6xo
April 8th

>https://www.youtube.com/watch?v=YjjEKIRr1JU
Drone footage of the crater and it's surroundings