Uncharted (adjective)

1. Not recorded on a map or chart.
2. Not well known or explored.

Origin:

Late 16th century: from un- (expressing negation) + charted, past participle of chart.

Examples:

1. The uncharted territory of the Amazon jungle was full of mystery and danger.
2. The uncharted waters of the Pacific Ocean were a source of both excitement and fear for the sailors.
3. The uncharted depths of the ocean remained largely a mystery to scientists.
4. The uncharted reaches of space were a source of fascination for the public.
5. The uncharted territories of the human mind were a source of inspiration for the psychiatrist.