Choose the caption bubble to begin. If you want to upload a custom bubble or alternative image then submit the caption first, then edit the comment and attach a "Place img". Once the image is approved you can use it by editing the caption again.
it was weird, youre only in the tunnel for like 20 mins.. i expected something a bit more dramatic i guess lol
otherwise its just countryside.. no offence to the french but i find the scenery in the north of france to be really, really boring :( its all flat you see
but other than that its awesome, not as much faffing around as u have for planes :D