I was looking for the most simple way of tracking the places I’ve visited. (If you ask why... I guess just because...for no real reason :) 
There are quite some tools out there that track your movements but most of them do that on a too detailed level and also store the location data in their (not my) databases. 
At the same time I did not want to run and maintain a database myself... now what to do?

Using git/GitHub as replicable time series database
I’ve written a small script that runs every day on my computer and my phone. It gets the current location through reverse geocoding and if the city changed it makes a git commit in a GitHub repository. The GitHub API allows you to do that through a simple HTTP request (documentation) . Through the same API you can also get a JSON representation of the commits (documentation) which then works perfectly as a travel log. Every visited place becomes a git commit, human and machine readable information is stored in the commit message.

The git repo becomes kind of a time series database speaking HTTP (through the GitHub API). And as a bonus: backups are a simple git pull. 

Here is the log: bumi/travels - and here a nice website for it.

I am currently in:  view log on github

And here are the last cities I’ve visited (since tracking started):

Update: You can set the commit timestamp to the future to also record your next stops. To do this use the --date option on the git commit command.

Do you have a recommendation of a place I should visit? Please create an issue.