Although planets are huge compared to our Earth, most illustrations show them deceptively large in proportion to astronomical distances.
One of my favourite pieces of information is that all the planets would fit between the Earth and the Moon.
Semi-major axis of the Earth – Moon distance: 384,399 km
Diameter of Mercury: 4,879 km
Diameter of Venus:12,104 km
Diameter of Mars: 6,779 km
Diameter of Jupiter: 139,822 km
Diameter of Saturn: 116,464 km
Diameter of Uranus: 50,724km
Diameter of Neptune: 49,244 km
The total sum of the planets’ diameters is 380,016 kilometers, having enough space to fit Pluto (2,372 km) and Ceres (950 km) as well.