A short but steep walk up the ridge behind the city center brings you to Signal Hill Observatory Platform, a wooden viewing deck that offers the best free panorama of Kota Kinabalu. On a clear morning you can see the islands of Tunku Abdul Rahman Marine Park floating in the South China Sea, and on very clear days the outline of Brunei's coast on the horizon.
The hill is also where the colonial-era signal station once transmitted messages between the islands and the mainland. The walk up takes about 15 minutes from the Atkinson Clock Tower area and is worth combining with a visit to the clock tower itself. Come in the early morning before haze develops or at sunset for the best views.