Ok, I have two ideas to bounce off you all which have nothing in common other than they are both kind of "Is shape superlative?" questions. And these are certainly not videos I'll be able to make for a while.
1. Is the ancient city of Angkor Thom the world's biggest square? The outer edge is an exact square with sides of 3km. I've been meaning to do a video about how Washington DC was going to be an exact square with 10 mile edges until Virginia took their bit back. But Angkor Thom is an actual 'solid' square (with a proper edge; it's not just a marked border). Let me know if you can think of another contender!
2. Is the phytoplankton Braarudosphaera bigelowii the world's smallest regular dodecahedron? I know there are virus particles like Adenovirus Dodecahedron but is that really a dodecahedron or is it just a clump of molecules with dodecahedral symmetry? And come on, look at the Braarudosphaera bigelowii, it's so incredibly a dodecahedron.
3. Let me know about any other shape suggestions (other than pointing out that CGP beat me to making a video about the hexagon on Saturn).