The highest source of the Mahaweli Ganga is a magnificent sight. The track your little group has been following leads past the river, and thunderous rapids cascade downwards as far as the eye can see, spewing foam and spray in every direction.
'The tomb of Tea Muasa lies on the other side of the source,' relays the guide.
'Thank you,' you reply, though this information is as apparent from the maps as the river before you.
The trail leads south, before curling east around the source of the water. From here the thick mountain forest blocks any further view of the river, but when you emerge on the other side, the sound of the crashing Ganga is defeaning.
All you can see externally of the structure is a single stone wall, set into the cliff of the higher mountains which rise before you. In the approximate centre of the stone is an open doorway, dark inside, and entirely unmarked, but also devoid of animal tracks or signs of human activity. According to the background information, tomb robbers were foiled throughout history by some unreported but apparently foolproof defences within. Sounds like just the job for...
You instruct your companions to remain and camp at the river source, with a strict warning to wait at least two days, and make your way through the forbidding portal.