I love building Nanoblocks! My favorites are landmarks and architectural structures seen around the world, like this one. These structures are challenging, but can usually be finished fairly quickly. Also, they don't take up much space when finished! You will need a pair of tweezers!
These Lego type blocks are so tiny! It is fun to put the model together and then if you have lots of models you can take them apart and build anything you want!! They are not for small children and make sure the pets do not get them.