Travel Best way to carry cash through airport and traveling

When I came to have surgery for the first time, I carried all of my cash in a belt bag which I kept on me under my clothes at all times during the flight. I am Canadian, I'm not entirely sure how different the procedure is for Americans, but I had to declare if I was bringing more than 10 000$ Cad out of the country, which I did. I declared the amount at customs, didn't take long they only had me fill in a form. When I was entering the plane there were custom agents which were stopping random people and asking their names, I had a feeling they were trying to find me to question me into more details about the money, but I'm not sure. Anyways, I couldn't be bothered, and I managed to enter the plane without them paying much attention to me.
When I arrived in Korea, I did not declare any money because I had a bit less than 10 000 USD, so I didn't need to. Anyways, just make sure you don't lose the cash and you tell customs you're bringing cash with you and you'll be fine
 
If it's a large amount, belt bags. Otherwise it goes in my wallet as it would anywhere else. But there's really little need to carry cash anywhere these days....
 
Crisp, new hundreds are the best way for me. I’ve found others (non-US countries) prefer new bills (some won’t accept any that is older than x years, usually under 10) and $100 holds more value than $20s.

usually I can carry $2-3k easily on my body. When I was younger my mom would put that in a ziplock bag and make me tuck it in my bra. Now that I’m older I rarely carry cash unless it’s to a country where I’m told cash is king but even then I carry a little and rely on my atm card for the rest.