Special/Unique 70th birthday gift ideas

Hi there,
Both of my parents have their 70th birthdays coming up this year and i'm looking for some unique amazing ideas for what to get for them. They are the type of people who have everything so i'm trying to think outside the box for something a bit different.
We are going on a holiday to Hawaii as a family to celebrate, but for their actual birthdays I want to be able to give them something.
Any ideas are very much welcome.
Thank you in advance for your help. =)