What Is The Saddest KDrama You Have Ever Watched?

what is or are the saddest kdramas that made you cry the most? 

Battle of Changsha. Based on the Japanese-occupation of China during the 1930s. Heartbreaking but very realistic drama.

49 Days
My Rosy Life
I'm Sorry, I Love You
A Love To Kill

Stairway to Heaven

I'm Sorry i love you will hold the number 1 spot for me

1 Litre of Tears,    for me at least i literally cried at least 1 litres of tears, if not more, watching this.
If you haven't cried in every episode after episode 2 then something is wrong with you, in my opinion at least.
It is also a very good Japanese drama to watch, highly rated, good actors with good if not great acting and the plot is amazing.
I honestly can't watch it again because it was that good if not great since it was that sad to watch, if you get what i mean?

@Sara - Same!! The only drama that made me cry was "Remember." I haven't finished it yet, but I should. It's so heartbreaking.

I don't watch too many sad dramas in general but 1 litre of tears---altho it's a jdrama---holds my number one spot followed by 49 days. I also cried buckets as I watched the kdrama special old farewell.