Is there a way to create and display a global 'Last updated' timestamp that would be displayed on every page? 'Last updated' would include adding and changing any piece of content on the website. I know how to display a similar timestamp for each node but I'd like to be able to display just one per page. Maybe looping through all created nodes and finding the latest date? How would I achieve that? Or is there a better solution - looping through all nodes might be memory-intensive, right?