万源市

万 = 丆 + ㇆ : As mnemonic symbol I choose a neuron, since each neuron is said to connect to 10000 others.

万 = 丆 + ㇆ : Willy Walrus needs to dig up the floor in the anthill's bathroom, but he is tired of doing so manually with a plough. To make his life easier, he sets up a wind wheel for electricity, connects a neuron to the wind wheel and the plough to transmit the electricity and uses his new DIY electric plough to dig much faster.

源 = 原 + 氵 : The origin (源) of the H bomb can be traced back to when Yu the Great (yu) once forgot a lot of water bottles (氵) next to her A bomb (原) in the anthill's kitchen (an2) and accidentally detonated the bomb.

市 = 亠 + 巾 : Mnemonic symbol: a supermarket.

Sherlock Holmes (sh) started a supermarket (市) in the space station's bathroom (Ø4), but all he has for sale right now are berets (亠) and towels (巾). He should have opened it at the beach!