Do Puzzles
Crosswords, Sudoku, and jumble puzzles are all ways to keep your brain active. Think of it as your daily walk around the block for your brain.
Travel
If a picture is worth a thousand words, seeing something in person could be priceless. New experiences and unfamiliar situations can be a good workout for your mind. While I’m not aware of any specific studies directly connecting traveling with a reduced risk of Alzheimer’s disease, traveling might be helpful for reducing your stress level, which has been connected with dementia risk.
A word of caution, however: Ensure that you’re in good physical and mental health before embarking on your adventure.