Today is my big day! In our life, we always try to find the cute and relevant answer to our being, Of course even the things that revolve around us. So, today is 21 and I'm wondering if you can give at least some reasoning to things that are significant about 21. 

To start, I'm sharing a few things that I know that have 21 but I still don't understand why they prefer to have it numbered as 21. 

1. Why is it called the 21 Gun Salute?

2. Why do we have a game in basketball first to finish 21 points?

3. Why 21 in Black Jack?

So, can you add other things that are significant to 21? Hope you can share!