Merge pull request #1978 from ipfs/fix-broken-link

Update merkle-dag.md

Author: 2color

docs/concepts/merkle-dag.md

@@ -13,7 +13,7 @@ A Merkle DAG is a DAG where each node has an identifier, and this is the result
 
 - Merkle DAGs can only be constructed from the leaves, that is, from nodes without children. Parents are added after children because the children's identifiers must be computed in advance to be able to link them.
 - Every node in a Merkle DAG is the root of a (sub)Merkle DAG itself, and this subgraph is _contained_ in the parent DAG.
-- Merkle DAG nodes are _immutable_. Any change in a node would alter its identifier and thus affect all the ascendants in the DAG, essentially creating a different DAG. Take a look at [this helpful illustration using bananas](https://media.consensys.net/ever-wonder-how-merkle-trees-work-c2f8b7100ed3) from our friends at Consensys.
+- Merkle DAG nodes are _immutable_. Any change in a node would alter its identifier and thus affect all the ascendants in the DAG, essentially creating a different DAG.
 
 Merkle DAGs are similar to Merkle trees, but there are no balance requirements, and every node can carry a payload. In DAGs, several branches can re-converge or, in other words, a node can have several parents.