Gorée Island - Île de Gorée, a Riven-like Mystery

Gorée Island - Île de Gorée is an island of mystery for the curious wanderer, with foot paths winding up and down around the island that lead to strange structures made in time gone past - a portal to where? Who built this, and why? Are they still here or did they step through to another dimension and time, never to return?

Tidal pools form in curious outcroppings of black lava pillars washed by a sea so blue, the waves' foam so white that one hesitates, is it real or is it virtual?

Silent and decrepit concrete pillboxes under the tropical sun shelter a lone cat, startling to encounter a living creature in this still and ominous mysterious fortification.

Pieces of heavy iron contraptions found strewn on the ground, housings, rails... how did they get there?  What purpose did they once serve?

Alleys lead to dwellings, entrances obscured by leafy canopies and tended flowers, with all the appearance of being inhabited, but seeming deserted, with no one to be seen, yet one knows they are there, somewhere.