I once had some bees that had settled in under my shower tray. The shower drain pipe passed along the shower room wall, through the outer wall, and emptied into the outside drain. (I live in a bungalow, by the way.) The hole, for the pipe, in the outer wall had not been cemented very well, so the bees were able to get into the house via that hole. The bees were discovered when a plumber came to replace the shower tray and cubicle. The bees were dealt with as efficiently as was possible, but some remained, under the shower tray, even when the hole in the outer wall was cemented up. For some days afterwards, bees could be seen flying close to, and up and down the wall, the former hole in the outer wall, as if they were seeking their relatives. The same activity was noted inside the house, with bees doing the same against the inner wall that backed on to the shower room. They seemed to be looking for a way in, to their old nest, or maybe to their friends and relatives. After a few days, the bees disappeared, but I suspect that the space around my shower drain pipe is something of a bees' tomb.