Travel meme from
You’ll need an atlas. Index Mundi can be useful, and though it doesn’t always provide links to latitude and longitude tables, once you’ve found the pattern /zp/[country code, though they don’t always use the ISO standard ones] e.g. UK you can prod it into action. (I’d add that even Wikipedia is pretty useful.)
What are the furthest points North, South, East and West you have visited?
These four points can be used to define a rectangle (well, in more-or-less spherical geometry they do) whose borders lie along the lines of latitude and longitude you have identified. What’s at the centre of this region? Have you been there? Where is the nearest place to the centre you have visited?
Farthest north for me:
Farthest east: Baku, Azerbaijan: 49.882 degrees east
Farthest west: SanFrancisco, California: 122.444 degrees west