Is it an open sewer? A soiled nappy? No, that wondrous smell is the fragrance of durian, the world's stinkiest fruit.
It honks so bad that in Singapore, it's illegal to eat it on public transport, and in a lot of Thai and Malaysian five-star hotels, you will not be allowed to eat the fruit within the grounds.
With news that Wing Yip - the chain of Chinese supermarkets - is about to start stocking Malaysian durian (it has stocked the Thai version for 30 years), we thought it was time to shine a light on this Marmite fruit.
First, locals absolutely love it. We're not talking about how you might like a Royal Gala apple - during festival season there is a frenzy for the stuff.
Celeste Brash writing on travel site Gadling, said about her durian conversion: "We cut open the fruit and dug in with our fingers, pulling out individual sections, each with a hazelnut-sized seed in the middle. The durian pulp was as slimy as I remembered, but without the smell bothering me there was no psychological barrier getting it in my mouth.
"Then, the surprise: It tasted like sugar cream, a little like creme brulee but with more personality. I took more bites and the flavor deepened. The overall taste was sweet, more wholesome than sugar, more pure than a peach or a berry; in fact it was the best sweet thing I'd ever eaten in my life."
However, if you're brave enough to try it, you will have to overcome the smell. Writing on XoJane.com, Zoe says: "It smelled like someone had been following around a bull mastiff with diarrhea for three days and storing the dog's poop in dirty socks."
While people love eating the fruit raw, durian can be made into desserts. Here Wing Yip shares a recipe for chocolate ice-cream:
Chocolate Durian Ice Cream
1 durian (approximately 300g of flesh)
50g cocoa powder
150ml plain yogurt
220ml whipping cream
Optional: Â½ vanilla pod, seeds scraped
1. Blitz the durian flesh, cocoa powder and sugar in a food processor, until it becomes smooth. If using a vanilla pod, add the seeds to the durian mixture at this point.
2. Place the durian puree into a clean bowl and add the yogurt, folding them together.
3. Whip the cream until you form stiff peaks. Carefully fold this into the durian and yoghurt mix.
4. Place in an ice cream maker and mix until the durian mixture becomes very thick and starts to freeze. If you donâ��t have an ice cream maker, place in a covered container and freeze. Stir every 20-30 minutes until the mixture is almost frozen, approximately 2 hours.
5. Enjoy on its own or with fresh berries.