My thoughts - Manaus, destination for birthday weekend

The P&O website has loads to say about Manaus:

"New York was built on granite, London on clay. But Manaus was built on rubber. As the furthest navigable port on the Amazon, some 1,000 miles from the ocean, the city sprang up as a centre for rubber exports from the Brazilian plantations and became a focal point for trade.
Taking its name from the Manaos Indians who inhabited the region, the city became a huge boomtown at the end of the 19th century, as more and more rubber was harvested from the surrounding rain forest.

As the economy thrived, the locals erected monuments to their success. The most flamboyant being the huge golden-domed Opera House, which was imported, stone by laborious stone, from Europe. At its height, it also boasted palatial mansions and a hedonistic life-style.
Nowadays, the rubber industry has died away, but the city, with its vast crumbling civic building, remains a fascinating gaudy metropolis, set amidst a sea of dense rain forest. "

This blurb makes the place sound exciting and worth visiting but what is definately worth remembering is when you view the Quickbird images of Manaus you see it is a huge city with a central business district, surrounded by residential areas surrounded by poorer residential areas. Very much like any other city. Much like London the town spreads itself along the river bank, but due to the width of the Amazon the city is entirely on one side of the river.

Am I getting excited about spending my birthday in a city like any other city? What am I expecting? What am I doing? I cant help but recall the words of my Rough Guide to South America which basically says that Brazil is one of the places in South America where you are most likely to run into trouble. Should I be spending my evening on the boat? Is the idea of spending my fortieth birthday up an ancient ruin with a bottle of local hooch no more than a pipe dream that is likely to leave me moneyless, passportless, and possibly even dead? Does doing this trip alone put me at more risk than actually travelling with someone? Is the independence of travelling alone worth the personal cost?

Which reminds me, I must get my will sorted out.