I was strolling in lisbon by the river tejo, next to the padrao dos descobrimentos monument when i noticed a strange cluster of lights on the sky moving at very high altitude. it was clearly visible as it was a dark night already with no light pollution on the river or left river bank where i was standing. the phenomena reminded me the pattern of a cloud of chaff or the light reflections on waves at the sea, except the ones on the sky moved steadily and seemed to glow and flicker, were very high above the few clouds (so much so i could not see the countours) and were following a straight flight pattern, from south to north at surely high speed -since the moment i saw them above the right river bank until they vanished from view on the city hills on the left bank around 15 mn passed, on a path that would have made it overfly the lisbon airport. and yet another strange fact; i am an aviation enthusiast and this summer as portugal and lisbon have become a much sought after tourist hotspot, i have been tracking for the past 2 months the arrivals of scores of planes, which land in large numbers from a sw flight path coming from the right (south) river bank of the tejo river, a bit off the bridge, every 5 mn or so. after the dissapearing of the strange lights from my visual standingpoint, i was much further intrigued by the fact that dozens of outgoing flights were now departing from lisbon airport not on the very common south-north runway axis but rather taking the usual inbound flight path, i.E., precisely on the opposite direction of the strange lights as if for some reason they were avoiding a possible crossing of their path. i am also a frequent flyer to man destinations all over the world and never have any of my flights took off across the city skyline, having inclusively to then make steep turns to go to their destinations as i observed yesterday. ps: i took one photo with my iphone se and a short video, where it seems there is a central cluster with small independent "orbs" next to it. also, apparently and as far as i can tell, dozens of bystanders, mostly tourists were baffled as i and taking pictures and videos with their smartphones, and furthermore i checked with portuguese ufo associations and this exact sightings have been multiplying this year alone mostly in lisbon area but also in algarve (southern tip of the country).