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                                                                   EXHIBIT 10.36


                      AMENDMENT TO OFFICE BUILDING LEASE
                      ----------------------------------
                                        


THIS AMENDMENT TO OFFICE BUILDING LEASE (this "Amendment") is entered into
                                               ----------                 
effective as of the 1st day of March, 1999, by and between THE PRUDENTIAL
INSURANCE COMPANY OF AMERICA, a New Jersey corporation ("Landlord"), and
                                                         --------       
FIRSTWORLD COMMUNICATIONS, INC., a Delaware corporation ("Tenant").
                                                          ------   

                                  WITNESSETH:

     A.   Landlord and Tenant entered into that certain Office Building Lease
("the Lease"), as of December 1, 1998, with respect to the premises known as
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Suite 208, comprised of approximately 7,108 rentable square feet (the "Original
                                                                       --------
Premises"), being a part of the building known as the Paragon Building located
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at 7100 East Belleview Avenue, Greenwood Village, Colorado (the "Building").
                                                                 --------   

     B.   Landlord and Tenant desire to amend the Lease to adjust the net
rentable square feet of the Premises, the amount of the Base Rent and otherwise
in the manner and form hereinafter set forth.

NOW, THEREFORE, in consideration of the premises and other good and valuable
consideration, the receipt and adequacy of which is hereby acknowledged, the
parties hereto agree as follows:

     1.   Additional Premises. Effective as of March 1, 1999, approximately
          -------------------                                              
5,979 rentable square feet, known as Suite 111 and depicted on Exhibit 1 hereto
(the "Additional Premises") shall be added to the Premises. The terms and
conditions of the Lease shall apply to the Additional Premises and the term
"Premises," when used in the Lease shall mean the Original Premises and the
Additional Premises.

     2.   Condition of Additional Premises. Tenant accepts the Additional
          --------------------------------                               
Premises "as is" and Landlord shall have no obligation for the completion or
remodeling of the Additional Premises.

     3.   Base Rent. Effective as of March 1,1999 the Base Rent, as defined in
          ---------                                                           
Section 3 of the Lease shall be Two Hundred Fifty Four Thousand Six Hundred
Thirty One Dollars and Ninety Six Cents ($254,631.96) per year and shall be
payable in monthly installments of Twenty One Thousand Two Hundred Nineteen
Dollars and Thirty Three Cents ($21,219.33) through the Primary Lease term.

     4.   Tenant's Pro Rata Share. Effective as of March 1,1999, Section 5 of
          -----------------------                                            
the Lease is amended to provide: Tenant's Pro Rata Share shall be 7.7%,
calculated on the basis of the
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ratio of the total rentable area of floor space in the Premises to the total
rentable area of the floor space in the Building, which shall be deemed to be
169,757.

     5.   Parking. Effective on March 1,1999, Paragraph 29 of the Lease shall be
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amended to substitute 43 for 24 parking spaces.

     6.   Miscellaneous.
          ------------- 

          a.   Tenant represents and warrants to Landlord that it has not
engaged any broker in connection with the negotiation and/or execution of this
Amendment except for Frederick Ross Company. Tenant has no knowledge of any
brokers' involvement in this transaction, except PREMISYS COLORADO, a Delaware
corporation ("Premisys"), which has acted as Landlord's leasing agent. Tenant
will indemnify Landlord and Premisys against any claim or expense (including,
without limitation, attorneys' fees) paid or incurred by Landlord or Premisys,
respectively, as a result of any claim for commissions or fees by any broker,
finder or agent other than Fredrick Ross Company, whether or not meritorious,
employed by Tenant or claiming by, through or under Tenant. Tenant acknowledges
that Landlord is not liable for any representations by Premisys or any other
broker or agent regarding the Premises, the Building or this Amendment.

          b.   In the event of any litigation arising out or of in connection
with this Amendment, the prevailing party shall be awarded reasonable attorney's
fees, costs and expenses.

          c.   The Lease as modified herein remains in full force and effect and
is ratified by Landlord and Tenant.  In the event of any conflict between the
Lease and this Amendment, the terms and conditions of this Amendment shall
control. Capitalized terms not defined herein shall have the same meaning as set
forth in the Lease.

          d.   This Amendment is binding upon and inures to the benefit of the
parties hereto and their heirs, personal representative, successors and assigns.
Except as expressly provided herein, Tenant has not assigned or transferred any
interest in the Lease and has full power and authority to execute this
Amendment. Tenant has no known claims of any kind or nature against Landlord
arising from or under the Lease and there are no agreements between Landlord and
Tenant other than the Lease, as amended hereby.

          e.   Time is of the essence herein, unless waived by Landlord, which
it shall have the right, but not the obligation to do.


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          f.   This Amendment shall be governed by and construed in
accordance with the laws of the State of Colorado.

          g.   The respective rights and obligations of Landlord and Tenant
with respect to the Original Premises shall be preserved and shall survive the
Surrender Date as to all matters arising or accruing prior to the Surrender
Date.

          j.   Tenant represents as follows:

               (1) Neither Tenant nor any of its affiliates (within the meaning
          of Part V(c) of Prohibited Transaction Exemption 84-14,49 Fed.Reg.
          9494 (1984), as amended ("PTE 84-14") has, or during the immediately
                                    ---------                                 
          preceding year, has exercised authority to:

                    (A) appoint or terminate the Prudential Insurance Company of
               America or Prudential Real Estate Investors ("Prudential") as
               investment manager over assets of any employee benefit plan
               invested in Landlord; or

                    (B) negotiate the terms of a management agreement with
               Prudential on behalf of any such plan;

               (2) Tenant is not a "related party" of Prudential (as defined in
          Part V(h) of PTE 84-14);

               (3) Tenant has negotiated and determined the terms of this
          Amendment at arm's length, as such terms would be negotiated and
          determined by Tenant with unrelated parties; and

               (4) Tenant is not an "employee benefit plan" as defined in
          Section 3(3) of the Employee Retirement Income Security Act of 1974,
          as amended ("ERISA"), a "plan" as defined in Section 4965(e)(1) of the
          Internal Revenue Code of 1986, as amended (the "Code"), or any entity
          deemed to hold "plan assets" within the meaning of 29 C.F.R. (S)
          2510.3-101 of any such employee benefit plan or plans.



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     IN WITNESS WHEREOF, the parties hereto have executed this Amendment to
Office Building Lease as of the day and year first above written.

                              LANDLORD:
                              -------- 

                              THE PRUDENTIAL INSURANCE COMPANY
                              OF AMERICA, a New Jersey corporation

                              By: CUSHMAN AND WAKEFIELD,
                                  INC./PREMISYS COLORADO, a
                                  Delaware corporation, as agent for The
                                  Prudential Insurance Company of America


                              By: /s/ Stephen M. Schwab
                                 ------------------------------------------
                                  Stephen M. Schwab
                                  Its:  Director
                                  Date: 3/5/99


                              TENANT:
                              ------ 

                              FIRSTWORLD COMMUNICATIONS, INC. a
                              Delaware corporation


                              By: /s/ Scott M. Chase
                                 ------------------------------------------
                                 Print Name: Scott M. Chase
                                 Its:  SVP Corp. & Gov't. Affairs
                                 Date: 2/22/99






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                                   Exhibit 1
                             "Additional Premises"


Exhibit 1 - "Additional Premises" includes a diagram of the paragon building, 
first level.