Going on a safari, climbing the Alps, or just needing something formal?
These New Zealand shorts are honestly much better than I was expecting. They are made of 100% wool so they may be itchy at first but once you get used to it, they become quite comfortable. 
These feature two waist pockets, belt straps, waist adjustments, and buttons to attach suspenders, so you have all the options to hold them up. 

I could not find more information on these, but the dated ones are from the 1950s. These do not look to be converted pants into shorts but were purposely made into shorts from the factory. 

Since these are over 65 years old, please expect moth holes, small tears, rips, and/or missing buttons. Aside from this, these are still in good condition and can be worn daily. They just need a little bit of care before doing so. 
 
Note on the wear. These do sit quite high, right over your belly button. To find your size, just take a tape measure and measure your circumference right at the belly button. Whatever the number is, is the size you should order.  
Sizes are in inches
 
These are so nice, that I had to keep a pair to myself.