It has occurred to me, since a brief visit back to Earth (or is it "Earth1" or "other-Earth?"), that there is an entire, and perhaps uninhabited world here. There is of course the desire to make public my discovery, but the nation in which the rift to Earth2 occurs would inevitably claim it, and a war with other nations would inevitably result. Claiming it personally in a public forum (which I now have the money to do) and grandly ceding it to the U.N. would  result only in the larger developed powers fighting over it, which would come down to development and exploitation, and I somehow can't abide that. I find myself becoming more concerned about the rift being discovered inadvertently, but I've taken steps to reduce the probability of that.
The weather has turned to spectacular storms, and the temperatures are dropping, indicating, I suppose, some seasonal change. May I then infer the cause to be this planet is tilted on its axis, like Earth1? Who knows? I'm snug enough here in the Tower. I can enter and leave much more easily, since installing an electrically powered lift from the ground to the window. This has the added benefit of making my stores in the Tower more secure. The lift can be locked out when I am exploring, and if it is damaged, I have retained the independent manual hoisting system, which is stored separately under a cairn at some distance from the Tower.
I now have provisions for a year, so I feel that I might become more adventurous in my exploring. This, however, will be a very gradual process, as I must continually establish caches of food as I move further from the Tower, each containing sufficient provisions to get me back to the one next nearest the Tower. I must never lose sight of the fact that none of the abundant life here is edible....except to each other.
I have killed my first Earth2 animal. Quite impressive, some local equivalent of a carnivore, certainly having the teeth and claws for it. Vaguely reptilian, at a guess 4-500 pounds, but it might just as easily be a mammal or something else inside....being wary that it might have been a member of a pack, I left quickly the way I came, and didn't even try to do an anatomy. It was one of those spontaneous encounters, and after months here I wasn't expecting it. Fortunately, the creature apparently wasn't, either, and I apparently looked different enough from the things on its accustomed diet that it stood watching me, as I quietly and slowly unslung my shotgun and made ready. When it made up whatever passed for its mind, it came for me quickly enough, and I put a series of 12-gauge slugs into its face. It dropped on the fourth, and there was not much twitching or evident pain involved. Perhaps I hit a vital spot and simply shut it off, perhaps those things just work differently with the fauna here. I must always remember to refrain from making assumptions drawn from Earth1 animals.
I have made a trip of 100 miles (a guess, but reasonable) from the Tower and returned, attempting to construct a map on the journey. A compass seems to work here, indicating an apparently consistent direction.

I spend my days cataloguing and taking photos of various features of The Tower and the artifacts it contains; when I weary of that, I explore more of the surrounding country. As to why there should be an apparent collection of the human past in The Tower, on this side of the rift -another place altogether- is a mystery I cannot fathom. I discovered the rift some years ago while hiking in a remote area. I decline to be specific about the location, for fear of the inevitable official reaction. My disclosure of the existence of the rift would have instantly resulted in its being made government property and classified as an utmost secret, and in all probability in my disappearance. For these same reasons, this writing will not be read by anyone until after I have moved through the rift- permanently.

This world, the world on the Tower side of the rift, is full of organic life....but it's not the life of Earth. Earlier, before I discovered The Tower, I took samples back with me and had them analyzed. Some plants that had apparent edible structures contained nothing digestible, while others appeared normal in some ways but contained toxins in their natural state, perhaps like manioc on Earth. One of the labs doing the testing sent me an letter after testing one sample, offering cash for a larger quantity, as the sample showed immediate and positive effect in alleviating inflammation of various kinds. I sent the lab an ambiguous response, then proceeded to systematically have other samples analyzed elsewhere, patented the resulting compound, and sold it to a major pharmaceutical manufacturer. The proceeds from that one sample from the other world has enabled me to devote all my time to its exploration.

I have not moved more than ten miles in any direction from the rift. The country is quit rough and steep. I must move slowly and take great pains to be safe, as there would of course be no possibility of assistance if I were to be injured. Further, since I have no sustainable supply of food here (although the water is perfectly potable), supplies of all kinds must be brought from Earth. I have thought about the possibility of the rift closing while I am here, but the presence of The Tower leads me to believe that the rift is permanent, or at least that I run little risk of being trapped here.

It is as if everything in The Tower has been collected and brought together to display in sequence the entire human record, indeed going back past Homo sapiens to the earliest ancestors possessing any human traits. After re-ascending The Tower and preparing a meal, I thought about what I had seen. The walls at the lowermost levels were painted with drawings that recalled the cave paintings at Lascaux or Chauvet in France, or Altamira in Spain, others unknown to me. Higher up had begun the familar wedge-shaped groupings of cuneiform writing, and directly above those Egyptian hieroglyphics- the pattern was already becoming familiar. Within 10 feet of the top of the stairs were represented languages of the day; I could recognize English, Spanish, French, and Cyrillic characters I assumed represented Russian. There were a variety of ideographic characters, although I could not tell whether they were Mandarin, Japanese, or some other. There were also stones inscribed with a complex series of hooked and dotted characters completely unfamilar to me. Strangest of all were the last three courses of stones....which were blank.
In the upper story, all of the other rooms contained shelves densely packed with books. I had no energy to open a single volume, however. I returned to my sleeping roll and was asleep within minutes.

I sat on the bottom step for an indeterminate amount of time, attempting to classify all the objects I saw before me on the floor. I had placed the gas lantern on a step about 10 feet off the floor, so that the room was illuminated by a light sufficient to see, but not in detail. I could see that the floor was littered with objects, but not the identity of each. I could see that the stones that made up the walls were covered with figures or inscribed, but could not tell the subject of the pictures or the type of writing.
I began using my flashlight to illuminate various items individually, in order to see each more clearly. The floor litter was comprised of items like stone tools, bones of various species, at at one place the charcoal and ashes of a fire. I could see among the stone tools the earliest "pebble" tools of Homo habilis, sometimes referred to as a "hand ax," entailing the removal of enough material on one end of a smooth stone to form a chopping edge- a design that remained unchanged through a million years.
There were other tools, in a bewildering variety, both flake and core tools of the Oldowan and Achæulian styles, as used by Homo erectus, as well as the highly styled and ground blades and points of the Neolithic. The dead fire, from what I could see at the distance I observed from, was littered round about with blackened bones, of what species not immediately apparent.
Behind the stairs was a hole next to the wall, approximately 1 x 2 meters, too deep for me to see to the bottom. I was determined to do the maximum amount of observation without setting foot on the floor, to avoid disturbing or destroying any artifacts or other objects....at least until I had formulated a plan for mapping and recording the original condition of every significant object.
The lower chamber was clearly shaping up to be a project in its own right. By this time I was hungry, so I ate some food I had brought in a small pack and gave thought to attempting some sort of overview of the rock walls that surrounded me as I made my way back up The Tower.

I descended 240 steps in total before I reached the bottom level of The Tower. There is more tower below the ground than above, for what reason I cannot imagine. The gas lantern shed a glow over the floor at the bottom of the staircase, and I could see that it was earthen, but scattered with objects lying about and protruding from the surface. I used my flashlight to shine its much brighter beam about, and the variety and types of objects I saw littering the floor made no sense.

Even after opening the window, I had no desire to enter The Tower at that point, as I had little strength left. I decided to descend, assemble supplies and make preparations to enter the next day, when I could re-ascend and explore on an extended basis. I returned to camp exhausted, lit a fire, prepared and ate a meal, went to my tent and slept.

I was awake at first light the next morning. I assembled food, drink and other supplies for several days, returned to The Tower and ascended. The pack containing my supplies I had left at ground level with a rope attached, and carried the end of the rope with me. After reaching the window, I entered and pulled up the pack. I primed and lit a gas lantern, which lit the room I was in with a yellowish-white glow. The room was lined with bookcases, apart from the mirror I had seen previously, as well as a door. The door led to a metal circular staircase that led up into an opening in a wooden ceiling, and down into the gloom. A railing surrounded the stairs, and I could see that there were doors at the other three compass points, all closed.
I was less interested at this point in exploring at my level than determining if entry to The Tower could be gained at ground level, so I decided to descend. I took the gas lantern, along with a large four-cell flashlight and a heavy revolver. I began to move down the stairs, while using the lantern to see what was around me in all directions. Figuring the stair risers at about 10 inches, and perhaps 10 feet to a story, I counted off 60 steps down, figuring that as approximately 50 feet, which was my estimation of the height of the window whereby I had entered. However, I observed no opening in the rock wall, only the rocks themselves, each inscribed inside as on the outside. After descending another 20 steps, I encountered a door in the wall. Relieved, and assuming I had miscalculated the height, I threw bolts back on the top and bottom of the door, and removed a large crossbar. However, the door would not open, nor move in the slightest degree. I had noticed there was a small window set in the door, closed by a metal cover. I turned the latch and opened the cover, and was mystified when my light showed only earth and small rocks on the other side. After several minutes lost in thought, I closed and latched the window cover, and continued my descent.

Yesterday I achieved entry. I had little success at first with attempts to lodge a grapnel in the far side of the roof peak. The tower is too tall, so I used bow & arrow to fire twine across the tower roof, and then used that to pull a rope over. Once the rope could be worked to the final on the end, it was simple to attach it securely. I then loaded the rope to three times my weight to test the strength of the attachment point, and it seemed perfectly solid. I then used a patent ratchet device to ascend to window level. The shutters had external metal hinges, which I employed as anchors to pull myself close to the window. I then used a pry bar to lever a shutter open; this required some effort, as the fastenings were surprisingly secure. I peered through the glass pane at the dimly lit interior, and saw only indistinct objects, apart from the sudden shock of seeing a human figure on the opposing wall. It was immediately evident that this was a mirror, and I was looking at myself clinging to the window. I used the pry bar to open the window, which moved inward with little effort, but a cascade of dust and a screech of rusty hinges. I was now able to enter The Tower.