In the Vedic Age trade was limited because of isolationism, causing people not to trade with each other poor roads, causing people to use the river ways to engage in trade poor trading products, causing people not to desire the goods others made widespread war, causing trade to stop between groups in conflict

the two atomic bombs dropped on japan in 1945 killed and maimed hundreds of thousands of people, and their effects are still being felt today. the uranium bomb detonated over hiroshima on 6 august 1945 had an explosive yield equal to 15,000 tonnes of tnt.

there are hundreds of postives ways to unite a country with another country here are a   few

1 peace treaty's peace treatys

are basically a document signing a allliance with one country and another.

2 gift

what i mean by this is for example how the french gave the americans the statue of libery a gift of peace.