I'm fascinated by the 26 Swiss Cantons. They're so distinctive, and I was delighted to visit my final one - Schaffhausen - last year. None disappoint, and all have delightful towns and villages. Some are very well known and are at the centre of the tourist industry - Bern, Luzern, Graubunden. Basel is divided into two, as is the lovely Appenzell. Appenzell Innerrhoden is tiny, and its eponymous mediaeval main town a delight. Zürich and Genève are quite densely populated and largely urban. The sizes, populations and population density of the 26 vary enormously. Graubunden has 3 main languages. Jura, Neuchâtel, Vaud and Genève are essentially French speaking, while Bern, Fribourg and Valais have the imaginary ‘Röstigrauben’ running through their territories, French to the west, German to the east, and a degree of dual language in the middle. The Schaffhausen boundary dances around its Bavarian equivalent.
Some were pioneers in the creation of Switzerland - eg Uri and Schwyz, while Jura only managed to split from Bern in the later twentieth century after a lot of voting and trying. One town, Moutier, seems to have just succeeded after many attempts, to switch separately from Bern to Jura.
Fribourg and neighbour Bern have some weird boundaries, with several enclaves and exclaves - no doubt the reasons are steeped in historical complexity and power statements by those of influence.
You might have to search on the map for less well known Cantons - Glarus, Solothurn, Oberwalden, Niederwalden. The Canton capital in Glarus has the most beautiful station, a real statement of regional pride.
Each of the 26 Cantons uses a simple 2-letter identity, often used to identify towns with the same name, eg Buchs SG (St Gallen) and Buchs AG (Argau). A good game for kids (I'm a big one) is to spot different two-letter codes on vehicle registrations as you move around the country.
Of course, the Cantons often have distinctive building styles, timber, brick, stone, steep or shallow-roofed, though these often merge into neighbouring areas. Perhaps the most distinctive is Ticino.