Some time ago I published an article diving by day in this cave that is located 18 meters deep in Cabo de San Martín and that gets its name because inside there is a stone block with an image of a virgin (Virgen de los Desamparados).

It is a siphon-shaped cave and, although you do not need to be an advanced diver, you will have to be careful both when finning so as not to raise the mud on the bottom and to control buoyancy during the ascent through the siphon.

A part of the cave, by day.
A part of the cave, by day.

In this video you will be able to appreciate the absolute darkness of the sea at night, as well as the contrast of the colors illuminated with a flashlight in that same darkness.

At night the colors are better appreciated than during the day, thanks to the flashlight and the contrast.
At night the colors are better appreciated than during the day, thanks to the flashlight and the contrast.
The seabed of the cave is full of mud that you can kick up if you’re not careful with the fins.
The seabed of the cave is full of mud that you can kick up if you're not careful with the fins.

You will also be able to appreciate how that same darkness provides absolute calm at times, but also overwhelms at certain moments (which you will notice in the breathing), for example when going up the siphon (almost at the end of the video), since when looking towards above (so as not to hit yourself when entering through the siphon hole), the second main stage (the regulator) offers much less air so, if you don't know it or are not used to it, that lack of air can be very oppressive.

LED light placed on my diving partner’s air tank, which indicates his position at all times.
LED light placed on my diving partner's air tank, which indicates his position at all times.
You have to approach very much to see clearly the image, wether at day or night.
You have to approach very much to see clearly the image, wether at day or night.
Exit from the cave through a hole in its ceiling.
Exit from the cave through a hole in its ceiling.

Video recorded with a GoPro Hero 8.

Photographs are screenshots taken from my videos.