How was this amount of zoom created by the water droplets on the concave lens of my glasses?
First, the typical magnification one gets from a drop of water is only a factor of ~4-5, not 10s to 100s. It is possible to construct micro-lenses from water droplets as discussed here https://www.nature.com/articles/ncomms14673, however that wasn't done to generate high magnification but rather to focus light from individual locations with a high spatial resolution.
...a single cell was zoomed in to the level where I could see the nucleus in the center, some squiggly organelles outside the nucleus and an irregular cell membrane around it.
Are you sure what you saw wasn't within or on the water droplet? There are lots of smallish bugs/animals in water and on your face/glasses that could be magnified by a water droplet. Since you state the source of the water was rain, it's more likely the small critter was already on your glasses (glasses can be rather nasty afterall).
There are lots of micro-animals like tardigrades, myxozoans, rotifers, nematodes, and loriciferans, many of which can look like a cell. I would guess this is a much more likely explanation than a single water droplet actually generating microscope-level magnification allowing you to see single cells, which are on the micron scale.
It is not possible to take a picture of this phenomenon. Probably the cells are in my eye.
This is unlikely. The amount of light that is reflected off of a water droplet vs transmitted is low (e.g., see https://en.wikipedia.org/wiki/Electromagnetic_absorption_by_water), which is why you can see through them.
It is possible you have some small organisms in your eye, but that the water droplet provides a magnified reflected image is unlikely. The most likely answer is the one I propose above, namely, that there are micro-animals on your glasses that are being magnified by the water.
The maximum angular resolution (e.g., see visual acuity) of the human eye is ~0.47 arc minutes or ~28 arc seconds. Typically ~1 arc minute is considered to be good vision. The smallest objects resolvable by the human eye are limited by the diffraction limit of the pupil and come in around the width of a typical human hair or ~55-75 micrometers (e.g., see https://en.wikipedia.org/wiki/Naked_eye).
So if we use the magnification of ~4-5 I mentioned above, something that is acutally ~0.055-0.075 mm in size would appear to be ~0.22-0.30 mm through an ideal water droplet. To put it another way, assuming the above and ideal conditions, the smallest resolvable objects through a water droplet would be ~0.011-0.015 mm.
With all that in mind, I note that the size range of single-celled organisms is rather large. There are bacteria that have cell diameters of less than a micron while some protozoans can be more than 100 microns.
Thus, in principle, it is possible that a large, single-celled organism was magnified and visible to your naked eye through the water droplet and your glass lense. However, I still maintain the more likely explanation is that there were some micro-animal-like critters on your glasses that were magnified by the water droplet.
Side Note
Depending on where you live in the world can also influence whether there is a significant probability of small micro organisms existing within the water drops from rain fall, i.e., they are inside the rain drops before they hit the ground. So I initially argue this is less likely above, it is not impossible for the rain water itself to contain micro organisms, e.g., see https://www.nature.com/articles/s41545-019-0030-5.
There is enormous energy in a storm, which will be randomly oriented with respect to a bell tower.
The energy in the bell's sound will be radially falling with $1/r^2$ and is not directional. The energy that a man can input to the bell ringing is limited.
The physics answer must be: there is no connection.
Then the question becomes metaphysics, the bell ringing raises the religious impulses of people to diffuse the storm. Are prayers effective? Uneducated religious people in general seem to believe so. Physics has not reached the level of detecting whether there is anything in metaphysics, (from telepathy to, in this case, manipulating storms)
Taking the expectation of bell ringing to defuse storms as a metaphsyics experiment, the answer seems to be "prayers are not effective"
Churches and castles were often extremely dangerous buildings during thunderstorms in the days before the lightning rod was invented. Being so tall, they were highly vulnerable to lightning strikes: hundreds of bell-ringers across Europe were killed over the centuries in the mistaken belief that ringing the bells would ward off lightning. But an even greater hazard was the habit of storing gunpowder in castles and church vaults.
Best Answer
The very fine droplets on the window act as a diffraction grating. In principle, a single droplet would produce (very faintly) something called an "Airy's disk" pattern. If they are all the same size, and the light is monochromatic, these will add constructively to make a clear ring. But in reality the droplets are many different sizes, and the light is not monochromatic. Consequently what you see is the sum of many of these patterns summed, each of a different size: this is the halo you see.
The faint ring you saw when you stepped out of the car may have a different origin. It may be that you had very small droplets on your glasses (did you step out of an airconditioned car into a humid night?), or it may be there were other objects (small droplets from fog beginning to form?) that were generating this pattern. The smaller the spheres, the larger the ring. The more uniform the spheres, the more it looks like a ring rather than a disk.