Category: stego · Artifact: extracted/roof_of_africa.jpg (1600x1056 JPEG)
Hint
"…protected by the mountain's most famous number."
Africa's highest peak = Kilimanjaro, 5895 m. That number is the steghide passphrase.
The challenge image:

Solve
1steghide extract -sf roof_of_africa.jpg -p 5895 -xf roof.txt
2cat roof.txt
(steghide info shows the file has embedded data; the mountain's height is the only key needed.)
Flag
hiCTF{h4kun4_m4t4t4_m34ns_n0_w0rr13s}
("hakuna matata" = no worries - a nod to the mountain/lion theme.)