Bogor is a town south of Jakarta that is in grave danger of getting swallowed by its big neighbor. The train station spits out passengers directly into a shantytown bazaar made of tarp and corrugated metal, very crowded and dimly lit. At the opposite end of the bazaar, across a small street, is the Abu Pensione hotel with faded awnings and signs that have lost the "i" at some point. But inside the rooms face a nice little garden, and they have two pleasant terraces facing the river flowing in a deep overgrown ravine.

Uncharacteristically for Asia, Bogor's heart is a huge botanical garden, beautifully landscaped with trees and plants from many countries, a lake, an orchid house, and a zoological museum with lots of tired dioramas with stuffed animals and a huge blue whale skeleton (not stuffed). A little dilapidated like the government museum in Chennai but very earnestly done.

On the way back it started raining - Bogor is the City of Rain - and waited it out at the Mata Hari department store. Outside, small barefoot children with giant umbrellas offered their services. One gust of wind and the sky would be full of floating children.

Took the ferry back to Uleh Leh, VIP class this time. They are running a Karaoke video of '60s rock songs. A becak driver took us into town, chatting all the way.

Banda Aceh is known to the world as the place of a civil war between a fierce Islamic separatist movement and the military of a repressive regime, and the place where the 2004 tsunami struck hardest and left much of the city in ruins, and washed away an entire residential suburb close to Uleh Leh harbor. The pictures on the world's TVs showed a single mosque in the middle of all the rubble still standing. We visited that mosque; it's beautiful ornate five-domed building gleaming white in the sun, with black domes. The city around it has been repaired and rebuilt, and now looks much cleaner and much better maintained than other cities of its kind elsewhere. Even the suburb towards Uleh Leh has been rebuilt with prim little houses, gardens, and driveways with SUVs. Banda Aceh is back on the map; it's not rich or packed with tourist sights but it has become a very pleasant place.

Everyone here is very open and friendly. People keep calling out to us, not because they want to sell something but because they are genuinely curious and would like to chat a little. We usually conclude after a few minutes that we don't share enough English, but that we enjoyed talking, so we say goodbye and smile and wave. Until the next chat. When we were ready to leave for the airport, it started raining and we didn't see a taxi, so some shopkeepers found one for us. The driver later stopped at the edge of the freeway to give us his name and number. It's all very pleasant and relaxing, I wish more of Asia would be like that.Anyone who thinks that Muslim countries are necessarily strict and cheerless places should visit Banda Aceh, and stay a little rather than rushing to the islands.

We flew to Jakarta because the southern half of Sumatra is not interesting; much of Indonesia's oil industry is there. At 19:52 local time, we crossed the equator. Another first; I had never been on the southern hemisphere. We are now in Jakarta, Indonesia's capital on the island of Java.

There is no beer on the island, officially. Sumatra is Islamic. But they aren't too religious about Islam here so they smuggle beer to the beach, and store it in a separate refrigerator and list it on the menu as "B". A can costs as much as a meal but it's not going to run out.

Elsewhere, like in Medan, you see women wearing a full-body burkha leaving only an eye slit, a fashion I call Black Raven. Which is actually more a cultural thing; Christian Europe also required women to cover their hair and skin five hundred years ago. But medieval customs meet modern technology when a fully veiled black raven is intently pecking at her cell phone. I imagine that she is twittering something like "my burkha itches". Other women wear a veil that leaves only their face free, plus skintight shirt and pants. They'd get flogged for that in benighted countries like Sudan, after the mullahs recover from their heart attacks. Here on the island you do ok if, in the words of a restaurant owner I talked to, you don't swim nude or have sex on the beach. That's only two rules away from some places in Thailand.

Anyway, I digress. Did another dive with Jim, minus the theory this time. It was much easier this time to breathe to control depth, rather than getting oxygen, automatically without thinking, and overcorrection was almost gone. We had 45 minutes to float at a depth of 12 meters, watching corals and fish far more colorful and varied than the ones near the surface we saw when snorkeling. Jim pointed out clownfish (now called Nemos), spiny lionfish that look like flying dozens of flags, toadlike stonefish than change color to match the background, and long thin trumpetfish hanging heads down. It's great to watch the other divers floating in the blue water weightlessly, with streams of bubbles rising up. The surface is invisible.

No scuba diving today. We rented snorkeling equipment instead and explored the bay for three hours. They have quite a lot of corals close to the beach, green, yellow, brown, sometimes with blue tips; in all kinds of shapes from big mushrooms to spindly treelike ones. Fish dart in and out of the corals and in swarms around them; black, blue, green, orange, white. Blue starfish and black spiky sea urchins cling to the corals. You can just go on and on in the warm water and stare at the scenery below.

For some reason the local cuisine deep-fries anything. Chicken, prawns, any meat, even bananas. But the fruit and juices are great. Papayas at home are very bland compared to what they serve here.

Pulau Weh is an island in the Sea of India off the northern tip of Sumatra. We chose Kabang Beach to stay. That's just a beach, not a village, and it looks exactly like a beach on a tropical island is supposed to look like: green warm water, a crescent of white sand lined by palm trees, and a few huts with restaurants in front of a hill behind the beach. Perfect. Primitive beach huts are available but we chose the Lumba Lumba dive center, which has a number of stylish, spacious, and comfortable bungalows set back from the beach. The dive center is run by a very helpful and friendly Dutch couple.

The atmosphere was somewhat infectious, so we asked for diving instructions. They had a slot right away, so in the early afternoon we found ourselves kitted out with a wet suit, weights, tank, BCD (buoyancy control device), regulator (the mouthpiece), flippers, and masks, after a 40-minute intro movie and a short diving lesson. They have a liability release form too.

We first practiced the Four Skills in shallow water: breathing under water (NEVER hold your breath or your lungs explode), clearing regulators, recovering a lost regulator, and clearing masks. Also equalizing, which balances air pressure in your ears to keep them from exploding. We then went diving in a reef not far from the beach, ten meters down, and practiced diving maneuvers, and watched fish and corals, including a gorgeous lion fish. The stingray was hiding. We later looked them up in a book. Diving is fantastic, we are trying to get another slot on their schedule.

Saturday was mostly a travel day. Settled the hotel bill - 65 euro for two people, three nights, and all meals and juices - the ferry to Parapat, a minibus to Medan, and a flight to Banda Aceh. There is a restaurant with a juice bar at the airport, but no matter what you order ou get either orange or apple juice. They have bottled juice too; one list of ingredients says "100% pure sugar". The schedule displays showed a noise Firefox connection error, and the gate displays said "no signal" so the flights were called out by an attendant.

A strong thunderstorm delayed the flight for one hour, and then the airport bus from the gate to the plane got stuck for 20 minutes in traffic on the apron, which led to honking and some daring passing maneuvers in front of the airplane. The Prapat hotel in Banda Aceh looks like an American motel, except that it's primitive, loud, expensive, and has no hot water and no sheets.