The NatGeo Explorer set out from Djupivogur to start a circumnavigation of Iceland in a anticlockwise direction. On the way, we came across a pod of humpback whales so the Explorer hung around so we could enjoy them for quite a while. The northernmost point in Iceland is the tiny island of Grimsey, 5km2, 40km off the coast and a truly fascinating place if only because its own northern tip is the only part of the country within the Arctic. Iceland's mainland is all south of the Arctic Circle. Grimsey is a strange windswept place featuring basalt cliffs, green fields and quiet coves. Its population of 61 is vastly exceeded by thousands if not millions of seabirds.
The fishing port of Sandivk in Grimsey was not big enough for the Explorer, so we came in on Zodiacs. 
The Miðgarðakirkja church in Sandvik, Grimsey was first built in 1867 out of rubble. This incarnation is made of timber. 
Grimsey is treeless. Indeed Iceland is mostly treeless. When Vikings first arrived more than 1000 years ago, it is believed that 40% of the area was wooded, but the newcomers harvested these forests for housing and other constructions. Deforestation has done the country no good what with soil erosion, desertification and the loss of already limited biodiversity, and there are now determined efforts underway to retree the nation. We saw some patches of new forests, but mostly the trees are pretty small. An Iceland joke: if you get lost in a forest in Iceland, just stand up!
It was quite a walk on Grimsey, up past the local airport, to incredible bird cliffs on the north side of the island where those oh-so-interesting puffins nest in their thousands, then to see the Arctic Circle markers, and more bird cliffs on the way back on the other side of the airport and past a lake replete with a huge swarm of kittiwakes.
On the way to the bird cliffs, the group uses walking poles as a defence against attacking arctic terns. 
Puffins have small wings and don't fly too well, but they are skilled at taking advantage of thermal updrafts. 
The Arctic Circle is the southermost latitude at which the sun doesn't set (at the Summer solstice, 21 June 2023, 'midnight sun') or doesn't rise (at the Winter solstice), and thanks to the earth's axis wobbling somewhat, the Circle is not fixed. Wikipedia says it is currently at 66o33'49.6" north of the equator and drifting north at 14.5m/year. Grimsey sports three permanent markers to show the position of the Arctic Circle in 1717, 1817 and 1917. In 2017, a moveable monument, and 8t stone sphere, was placed and it is moved occasionally to the current correct location. In the not too distant future, the marker will have to be dropped into the Norwegian Sea!
This is looking north across the treeless expance, so the Arctic Circle marker has only so much life on Grimsey. 
Being on the Arctic Circle, it's easy to imagine that travelling further north increases the distance from Australia, but, for the geeks, this is not true. Anywhere north of, say London, is heading back to Australia on a great circle route via the North Pole and Japan. There are no such commercial flights as far as we know, and flightconnections.com tells us that the most direct flights from Iceland to Sydney are via Vancouver in Canada, just one stop. The actual antipode of Sydney is near Portugal, and the antipode of Iceland's capital Reykjavik is in the Southern Ocean, about 2500km south of Hobart.
Grimsey is a tiny island at the top of Iceland, and only its northern-most point is within the Arctic Circle.