millisphere (noun): A discrete region inhabited by roughly 1000th of the total world population. Around seven million people but anywhere between 3.5m and 14m will provide a lens to examine human geography.
Last month Rwanda's president, Paul Kagame, was sworn in as chairman of the African Union, so this week I talked with two women from Whanganui about their time in Rwanda.
The 1994 genocide, when 800,000 people were murdered by their machete-wielding neighbours, still keeps tourists and travellers away but, by all accounts, Rwanda is now one of the safer places to visit in Africa.
Landlocked high on the watershed between the Congo and the Nile, and with fertile soils, Rwanda is beautiful and the people humble, Pam and Anne, who went there to volunteer in an orphanage, told me.
It is also one of the most densely populated countries in Africa.
Apart from a handful of Muslim countries in the Middle East, the world's fastest-growing populations are in sub-Saharan Africa, and Rwanda's population is growing at 2.4 per cent each year, while 20 other African countries are growing faster, including Rwanda's neighbours Burundi, Democratic Republic of Congo (DRC), Tanzania and Uganda.
Rwanda (2015 population 11.2 million) is mostly Christian, with a small Muslim community. It is also divided into Hutu (86 per cent) and Tutsi (14 per cent).
Conflict started with a Hutu revolution in 1959 when the Tutsi monarchy was deposed and 300,000 Tutsis were forced out of the country.
In 1994, a plane carrying the presidents of both Rwanda and Burundi was hit by a rocket shortly after leaving Kigali airport, followed by the assassination of the moderate Hutu prime minister. The army and bands of Hutu "Interahamwe" (those who attack together) then attacked Tutsis with whatever weapons they could lay their hands on.
Hutu extremists were thought to be responsible for the rocket attack but the Tutsi Rwandan Patriotic Front (RPF) and even Paul Kagame have not been ruled out.
Kagame's RPF then took the capital, Kigali, and two million Hutus fled into the DRC — Anne's orphanage was near Lake Kivu on the border with the DRC.
In 1996, the Hutu/Tutsi conflict spilled over the border into the Congo (then known as Zaire) and another five million died in the DRC. Because of the huge number of genocide cases, the accused are tried in "Gacaca" courts, traditionally used for disputes between families.
Pam saw chain gangs dressed in different coloured overalls, depending on the crimes they had committed, maintaining Rwanda's roads — "I think the murderers wore pink overalls and lots of people had horrible machete scars," she said.
Pam also visited the Diane Fossey Research Centre in Karisoke, where the mountain gorillas live. "There are armed guards with the gorillas all the time to stop poachers."
American TV host and comedienne Ellen DeGeneres has recently established a wildlife fund there.
Since the RDF takeover Rwanda has enjoyed economic stability and the Rwandan army punches well above its weight in the region. Kagame is "genuinely popular" although his enemies "tend to die".
Kagame's ambition is to make Rwanda "the Singapore of Africa", and the capital Kigali is sprouting high-rise office buildings and the county has the densest road network in the region, 20 per cent of it paved.
Landlines are insufficient but they are rolling out fibre optic cable and mobile phone ownership is growing rapidly. Along with its neighbours, Rwanda has agreed to phase out the import of second-hand clothing and shoes from the First World.
When tourists arrive any plastic bags are confiscated, Pam and Anne told me. Rwanda is a plastic bag-free country, there is no graffiti and the last Sunday of the month is a "rubbish pickup day".
Rwanda today is an oasis surrounded by ongoing conflicts and, as head of the African Union, Kagame faces many challenges.
"The temptation to link the entire conflict in Rwanda with overpopulation and competition for resources is irresistible," said NZ economist Gareth Morgan when he passed through on a motorbike. This goes for much of Africa today.
■ When Fred Frederikse is not building, he is a self-directed student of geography and traveller, and in his spare time he is the co-chair of the Whanganui Musicians' Club.