Landownership is inherently a monopoly, since it is impossible to manufacture or import space, or to create more material natural resources such as oil and minerals. If you want to be a landowner, you must either obtain land from someone who already has title or discover land that nobody has claimed yet. Since the solid surface of the earth is now all discovered and under the jurisdiction of countries, the landowners and governments together now have a monopoly on the usable land on earth. This monopoly is coercively imposed on those who don't have a share of land, unless the natural benefits, manifested as rent, are equally shared. Small-scale ownership would be less efficient.
Natural monopolies are typically utilities such as water, electricity, and natural gas.
It would be very costly to build a second set of water and sewerage pipes in a city. Water and gas delivery service has a high fixed cost and a low variable cost. Electricity is now being deregulated, so the generators of electric power can now compete. But the infrastructure, the wires that carry the electricity, usually remain a natural monopoly, and the various companies send their electricity through the same grid. To prevent utilities from exploiting their monopolies with high prices, they are regulated by government.