Here is data about the largest domes by diameter of various types from this list:
The Global Vipassan Pagoda in Mumbai, India (2006) has the widest stone dome in the world, at 86.15 meters or 279.4 feet.
The list gives the previous record holder as the Western Thermae in Gerasa, Jordan, (2nd Century AD) with a diameter of 15.0 meters or 49.2 feet.
However, another part of the list mentions the dome of the Gol Gumbaz, Bijapur, India (1659) at 44.0 meters or 144.36, which I think is also made of stone.
And I believe the dome of HItler's planned Volkshalle in Berlin would have made of stone and have a diameter of 250 meters or 820 feet. A plan for the railroad station in Munich called for a dome 265 meters or 869 feet in diameter.
The widest reinforced concrete dome was the Kingdome (1976-2000) in Seattle, Washington at 201.17 meters or 660 feet. The previous record holder was the Norfolk Scope (1971) at Norfolf, Virginia, 134.1 meters or 440 feet.
The largest steel dome is the Singapore National Arena (2013) at 310 meters or 1,017.1 feet. The previous record holder was the Louisiana Superdome (1975) at 207.0 meters or 675.1 feet.
The widest wooden dome is the Superior Dome, Marquette, Michigan (1991) at 163.4 meters or 536 feet. It is a geodesic dome.
Richard Kirk mentioned that a one mile wide geodesic dome is feasble on Earth, about 10.095 times a wide as thelargest existing one. And possibly in some cases domes of other typescould be built ten times as wide as the widest existing examples of their types.
So there is no evidence that the present largest dome of a type is the largest possible dome of that type. Probably significantly larger domes of each type could be built on Earth. And of course on the moon with lower gravity and thus lower stresses on structures, a dome could probably be built much wider than the widest possible dome of that type on Earth.
The fourth largest buildng by volume on Earth is not supported by any columns. It is the Aerium in Hallbe, Brandenburg, Germany (2000). It was built as an airship hanger and now houses a tropical beach resort. It is 210 meters (688 feet) wide, 360 meters (1,181 feet) long, and 107 meters (351 feet) tall.
At 5.5 million m³ (194 million ft³), it is one of the largest buildings on Earth by volume, and is the world's largest single hall without supporting pillars inside.
The covered dry docks for ship building at the Meyer Werft shipyards at Pappenburg, Germany are also huge.
"Dockhalle 2" is the world's largest shipbuilding hall. This is the world's first covered dry-dock - opened in 1987. The hall has length 370 m (1214 ft), width 101,5 m (333 ft) and height 60 m (197 ft). In 1991, the drydock was extended with 100 m (328 ft). In 2004, here was constructed a second roofed drydock, that was later extended to 504 m (length), 125 m (width) and 75 m (height). The project resulted into building capacity of 3 cruise ships a year.
An enclosed space without columns 504 meters (1,653.54 feet) by 125 meters (410.105 feet) by 75 meters (246.043 feet) has even more square feet than the Aerium.
I note that the widest clear span roof in ancient times was in the throne room of the Flavian Palace in Rome (1st century AD) with a span of 31.67 meters (103.9 feet) though its existance is uncertain. The widest clear span of a surviving Roman roof is that the Aula Regia or Basilica at Trier Germany (early 4th century aD0 with a span of 26.05 meters (85.46 feet).
So there has been considerable progress in in roof spans the last 2,000 years.
Part two: Shellworlds.
A shellworld13 is any of several types of hypothetical megastructures:
A planet or a planetoid turned into series of concentric matryoshka doll-like layers supported by massive pillars. A shellworld of this type features prominently in Iain M. Banks' novel Matter.
A megastructure consisting of multiple layers of shells suspended above each other by orbital rings supported by hypothetical mass stream technology. This type of shellworld can be theoretically suspended above any type of stellar body, including planets, gas giants, stars and black holes. The most massive type of shellworld could be built around supermassive black holes at the center of galaxies.
An inflated canopy holding high pressure air around an otherwise airless world to create a breathable atmosphere.7 The pressure of the contained air supports the weight of the shell.
Completely hollow shell worlds can also be created on a planetary or larger scale by contained gas alone, also called bubbleworlds or gravitational balloons, as long as the outward pressure from the contained gas balances the gravitational contraction of the entire structure, resulting in no net force on the shell. The scale is limited only by the mass of gas enclosed; the shell can be made of any mundane material. The shell can have an additional atmosphere on the outside.5
Any of the first three types could be built on the Moon, with the tird type the least advanced technology.
I note that inflatable structures don't have to have a spherical shape. inflatable rubber rafts are an example. Holiday parades often involve giant ballons shaped like living beings who retain their complex shapes. I have seen photos of ballons shaped like buildings.
So builders on the Moon could build a flat airtight floor on the moon, with a triangular, square, rectangular, or hexagonal shape, and with some airlocks at the edges. And then they could attach an airtight fabric that has a roof shape dlike the floor with walls hanging doen to the floor (or to the airlocks, and attach the fabric to the floor and airlocks, make certain it is sealed airtight, and then inflate with a breatheable atmosphere. And a number of them could be built side by side connected by the airlocks. And possibly the vertical walls between connected balloon structures could eventually be cut away to make larger spaces.
And if the lunar regolith that was removed when they leveled the ground and built an airtight floot is then placed on top of the inflated areas, held up by air pressure, the enclosed areas will then be technically under lunar regolith and thus "underground". A thick enough layer of lunar regolith might provide protection against micrometeorites and solar and cosmic radiation.
On Earth air supposrted roofs have been built of considerable size but Ihav ebeen unable to find the larges tone.