Apart from your love for another human, what makes your heart ache?

The reason I ask this question is, today I was trying to work out when I might be able to go back to Scotland. Many of you may know that Scotland (especially the west Highlands) is my favourite place to visit and if I have long gaps between visiting my heart aches.

I am sure we all know that love of another person (whether it be romantic love or the love for an offspring) can make our hearts ache but I can honestly say I have never felt this kind of longing for a place before I fell in love with Scotland.

What (other than the love for another human) makes your heart ache?