Mountains
A line of symmetry divides a figure into two matching halves.
a hemisphere
The line that separates a shape into two matching halves is called the line of symmetry. When a shape is folded along this line, both halves mirror each other perfectly. In geometric figures, this line can be vertical, horizontal, or diagonal, depending on the shape's orientation.
Septum. Between the two atria is the Atrial Septum and between the two ventricles is the Ventricular Septum.
It is believed that the film will be split at malfoy manor
The Aegean Sea is between Greece and Turkey.
The sagittal plane separates the body into left and right halves.
The Equator (zero latitude) separates the Southern Hemisphere from the Northern Hemisphere.The Prime Meridian (zero longitude) separates the Eastern Hemisphere from the Western Hemisphere.
The Aegean Sea separates modern Greece from Asia Minor. The two Turkish straits (Bosphorus and the Dardanelles) are conventionally considered the border between Europe and Asia, but they are both within modern Turkey.
Two halves make a whole. Or You have two halves!?
The third ventricle
There are four halves in two wholes. Each whole is made up of two halves, so when you multiply two wholes by two halves per whole, you get four halves in total.