Carbondioxide and Gas.
Usually in marshy ground.
on the ground
A basement is a large room under the ground. A dungeon is a room under the ground.
Sulfuric acid falls from the clouds high above the surface of Venus, but it evaporates long before reaches the ground.
Mercury, Venus, Earth, Mars, Pluto
go under ground and find fossils
It was secret like being under ground.
No, they are under water but not under ground. There is no ground above them.
Pic pipe under ground
In the Solar System, that would be Mercury, Venus, Earth, Mars.
It is very thick. At ground level and at 20 deg C, Venus's atmosphere is around 50 times as dense as the Earth's.
There are 243 Earth days for a Venus day - but a Venus year is just under 225 Earth days. Therefore - a day on Venus is longer than a year !