db.venues.aggregate(

	// Pipeline
	[
		// Stage 1
		{
			$addFields: {
			  "firstChainId": {
			    "$arrayElemAt": [ "$chainIds", 0 ]
			  }
			}
		},

		// Stage 2
		{
			$lookup: {
			    "from" : "chains",
			    "localField" : "firstChainId",
			    "foreignField" : "_id",
			    "as" : "venueChain"
			}
		},

		// Stage 3
		{
			$addFields: {
			  "chainName": "$venueChain.name"
			}
		},

		// Stage 4
		{
			$project: {
			  n: 1,
			  chainName: 1
			}
		},
	],

	// Options
	{
		cursor: {
			batchSize: 50
		}
	}
);