Where do I live?

So I have some pictures of my house in Cambridge I took when I moved in but never got around to posting. Here we go!

So, I live in Malting House on little Malting Lane, marked in pink. The Law Faculty building is marked in blue, and the main entrance to Darwin is marked in purple:


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Here's the front of the house:



And, from this angle, you can see my window. I'm on the top floor on the right-hand side, the second window from the front (so I have a slightly sloping ceiling):



Here is a bit of the Darwin grounds:



This is the "Mathematical Bridge":



The (untrue) urban legend with that is that Newton built the bridge without bolts, but simply balanced all the wood on top of each other appropriately to build a bridge. Then, the students took it apart centuries later to figure out how he had done it ... and couldn't put it back together again. So now it does have bolts to put keep it in place. Of course, that story is totally untrue and it has always had bolts, but whatever.

Here is the front of the dramatic King's College:



Here is the market in the center of town, which is actually open every day but Sundays:



I got both my sunflower and my "flowering cactus" there, but we'll get to those in a little bit.

Here are some of the cows in one of the fields:



Here are some pictures of the big interior quad of King's:





And here is the River Cam and the Mathematical Bridge from another angle, showing some of Queen's College that is right up against the river:



Here's the River Cam from a different bridge/angle:



Here's Clare College, where Nick's brother, Chris, went:



And here's the "back" of Clare College:



All the colleges along the main section of the river have "backs" on the far side of the river, which seem to often just be grounds. So you live on the close side of the river to town, but then you can cross to more college grounds on the far side of the river.

And then, here are some pictures of my room, back in the Malting House:









So, this was my sunflower:



But the sunflower has gone on to a better place. So, recently, I went back to the Cambridge market in search of another, less fussy plant. So, this time, I got a plant that was labeled as a "flowering cactus" but that the consensus seems to be is a Christmas Cactus. Here is a photo:



So, the final question is, how do I make sure that this one doesn't go the way of the sunflower? Any suggestions? Like, how often should I be watering it?