Use the investigate (?) icon on the giant tree. Prof. Sim should come by.

I do have no clue how it happened. My Education suddenly reduced from 60 to 20 and at 51%
he came and asked me to build a museum. Last time that happened he DID NOT COME. So maybe
he comes randomly? :0

There are some simple steps:
1. Build the Archaeology Lab
2. Wait for it...
3a. Use investigate like I said earlier
3b. Just keep waiting.
4.?????
5. Profit!

1. Build the Archaeology Lab.
2. Wait a few years or so.
3. Professor Sim will come.

Make sure you don't demolish the Big Tree before professor Sim comes otherwise Maxis will
come and ask you to build a Drilling Facility. Also you don't need to press the
investigate button.

I have tried all of you have said, but prof. Sim doesn't come.
Maybe is because the zone of my city where I have built it or it is because I don`t have
to build the two other labs that prof.Sim asked me to build?
I have 70 education level and 84% approval.

Ok guys, i have proof that prof. Sim doesn't come randomly. (i have played it through
exactly the same 5 times juuust in case)
Prof. Sim comes when you make every upkeep 200% and do 3% for taxes! Well that's how i got
it anyway; i got the archaeology lab and 1 day after i built it prof. Sim came... Wierd...